If you look for the better cubes at a good price, I recommend:
- 2x2 Dayan $10 (on cubezz). Or maybe the Weipo is as good, I don't know (on cubezz its $9-10 too).
- 4x4 Cyclone boys G4 $9-10 (on cubezz, championscubestore, ...). If you like the mini size (60mm) is one of the better cubes if not the best and is cheap.
- 5x5 Cyclone boys $9-10 (championscubestore) or a Bochuang ~$16 (lightake or aliexpress)
And there are ~$65-70 left for a 6x6 and a 7x7. I would get the yuxin (~$25 on lightake, I bought it for $23 in aliexpress) and wait for the 7x7, because the Aofu is a bit expensive and maybe Yuxin will make one soon. But if you want, you can find ir for under $40 on aliexpress, so, your $100 would be enough.
For me, the biggest difference between the Yuxin 6x6 and the Aoshi is the size (65 vs 68 mm), the Yuxin is more comfortable, and I hope for a 7x7 much smaller than the Aosu, because brands are trending to smaller cubes (56mm 3x3, 60mm 4x4, ...).
PS: If you don't want to order from different stores, I think lightake have them all with a very reasonable prices, or you can search on aliexpress too for a seller who have them all too.