I need to get some weights, all I have are my sister's which are only about 4 pounds, way too light. Up till now I did a lot of exercises using body weight but that only lasts so long. So what range do you use? Do you hold heavier weights for leg muscle exercises (like lunges; they're getting too easy now) than upper body exercises?
I guess I want some in the 60-80% of my 1RM but I don't know what that might be. Ballpark figures?

Hm, if I was to get weights for home exercise, I'd get kettlebells, but that's just me. I'd get a pair of 8kg, a pair of 12 kg and a 16 kg, that should cover most exercises at my level.

I use a pair of 5, 8, 10, 12, 15, 20 & 25s depending on what I'm doing.

I use the tubes. You can get a set and range your weight from low to high with little expense. And they work your muscles in more ways. You can also vary your resistance by getting a set that had 5, 10, 20 lb as an example, but vary it even more by shortening the tube for more resistance. IMO, the most economical way to go.

This; this except i would also get a 44 pound as you progress, maybe even a 53 or higher depending how far you take it. I use Kettlebells and they're great for me.

I use weights in kilograms, but these are the approximate conversions--
22 lbs (10 kgs) pair
26 lbs (12 kgs) pair
33 lbs (15 kgs) pair

These get me through most of my routine- shoulder press, bench press, lunges, rows, etc. They aren't heavy enough for good squats though, but it's all my gym has .

Have you looked into adjustable weights? When I used to lift at home I had some and it was nice not to have to go back and keep buying new ones as I progressed.

As for me, I dead lift with 2x20kg+bar, and do arm work with 10kg weights, sometimes 14kg (for rows). We have a few machines at the gym that I do beyond that and I still do body weight exercises. At the moment I'm not using weights when I do squats due to my knees being bad and I'm not doing lunges at all, so I can't speak to either one of those.

Also, have you tried walking lunges?

I use 12 pound weights for bicep and tricep work. Use a bit lighter for shoulders.

OP, perhaps you can just try a few pounds heavier from what you are doing and do eight to ten reps (or whatever you are now doing) of three sets to exhaustion. If you can lift more then you are not lifting heavy enough.

I use the 45 pound straight bar for squats.

thanks everyone
i tried out some 5 kg weights for arm work, it was pretty good. i guess that's my starting point. i'll need heavier ones for deadlifts and squats, i think.