For ‘older’ knee’s potentially like Dave’s you could try some other fun variations:
Single Leg Swiss ball squats loaded or unloaded. You can control your knee angle as much as you want 
For the posterior chain:
Single Leg bridge, loaded and unloaded.
Single Leg Swiss Ball leg curls and if your advanced/adventurous you can try loading them too.
Skinny cyclist here: If I were looking for a basic squat / deadlift setup for the garage, what would you recommend? Not absolute bargain basement, but I don’t need fancy.
A set of adjustable dumbbells would probably work if you don’t anticipate lifting a huge amount of weight. I have a pair of Bowflex dumbbells that go up to 52.5 lbs each. The model is Selectech 552, you just twist a dial to change the weight, no taking off/putting on plates.
Goblet squats, lunges, step ups, and deadlifts are all easy to do with them.
Agree on the recommendation for dumbbells. Easy and sufficient for what most people need.
A barbell is really only necessary if you’re lifting heavy weights to build strength / weight for a power sport of some type. To be clear - I’m not saying barbell exercises aren’t good - they are, I did them for 20 years. But dumbbells are easier and offer more flexibility / range of exercises - and arguably are better for cyclists as they allow for a lot of single sided exercises.
For squats and deadlifts, when you do them single sided (eg split squat, single leg deadlifts), dumbbells will get you all the weight you need.
FWIW, if you go down this path, I’d recommend mixing dumbbells and kettlebells, as it allows for a greater range of exercises.
I’ve never been a fan of these. They are more bulky vs a regular dumbbell, and the plates can wiggle about sometimes which is off-putting.
If at the beginning of a strength program, and are looking to ramp up weights while containing the number of pieces of equipment, I can see they are very useful.
Once you reach “steady state” and are in maintenance mode, you don’t need the range of weights.
Lifting heavy meaning what? I was 1.2x for 5x5 bodyweight when lockdown started, but I don’t have any real goals, just increasing strength.
FWIW - also enjoy dumbbell movements in addition to barbell work.
For iron dumbbells, a potential issue is the standard 5 pound increments can be too much of an increase in one step.
Wife and I added a set of PlateMates to our dumbbell collection and find them very useful. These are overpriced but very effective 1 1/4 pound magnets that you stick to the dumbbell (or to iron plates for barbells) allowing smaller weight increments.
No affiliation, just something others might find useful and wouldn’t obviously know about.
Our fixed weight dumbbell collection goes from 5 to 50 pounds. Collected over time as we needed and not a matched set. Weight is weight.
Anyone have a preference and some reasoning behind preferring dumbbells or kettlebells? At this point I just need something heavy to add to my bodyweight strength training routine. Ideally for as little money as possible. I’m pretty shocked how expensive basic weight equipment is.
For the money and flexibility you cant beat a set of bands.
Beside the obvious - they take up much less space than barbells - I like them mostly for one-sided exercices which come with a few benefits:
On the other hand, I find one-sided exercices don’t quite tax the CNS in the same fashion as heavy barbell movements. I guess this can either be a pro or a con, depending on your goals.
Finally, as for going heavy on a budget - see my recommendation of the sandbag above. It’s a tremendous piece of equipment that can be had for relatively cheap.
I forgot that I have a set of bands! Or more accurately, I hadn’t considered using them for my Bulgarian split squats and single leg hamstring bridge. Thanks, that’s perfect! At least for now.
thanks for this detailed response! Hopefully soon I can get a sandbag and some other equipment. My plan is to keep looking at craigslist for deals.
I’ve had dumbells around the house for years and rarely touched them. I got a couple kettlebells about 8 weeks ago and can’t keep my hands of them. There’s your answer
I’m admittedly a recent convert but in my short time with bells, I have come to firmly believe that every human should be doing kettlebell swings a few times a week so even if you’re focusing on dumbbells, still get a kettlebell or two. There are lots of kettlebell exercises but they are worth it just for swings alone
Lastly, in the current Covid/home gym panic, kettlebells are a little easier to find than dumbbells.
I used an old ikea expanding shower rail with two tyres on balanced each end for a makeshift 20kg over head press, and the same rail with two carwheels for a 30kg squat bar, if I recall correctly. Military press on the kids garden swings.
It was a pain, and through lockdown I eventually sourced a rack, bar and weights. As someone who doesnt really identify with “lifting” its been a surprising source of pride this season.
Not heard of it - author?
My bits I sourced from half a dozen places because of lockdown so brands probably not useful? (Menshealth, Again Faster, Gorilla Sports, Fitness Superstore, StrengthShop, Decathlon) Im a newbie lifter, just doing 5x5 workouts in off season, as Im a long course triathlete. Just once or twice a week medium weight during in season.
Powercage (rated only to 200kg iirc)
15kg 6ft olympic bar
4x20kg
2x10
2x5
2x2.5
2x1.25
Flat bench
4m2 matts
All pretty much as cheap as I could find. If youre never going to your absolute limit, and only doing squats/deads you might go for a squat rack but they arent much cheaper than cheap powercages, I found.
I’d gift my ScientificTriathlon 19-week plan to you, if I could. Not currently using it but its a great plan.
Only one quibble with your list - a 6’ bar may work for many for squats but if you have long arms and/or tight shoulders your hands end up in the way if you use a wide grip making racking tough or even impossible. If you are only going to get one bar, consider a 7’ (which is the standard length for squats) unless you’re absolutely sure 6’ will work for you.
Oh yeah, actually that was a concession to the width of my garage!
Somewhere in that range is where I think it makes sense to start using a bar.
At 1.2x though, I’d probably still use dumbbells . Some round math as follows: