The prices are different because they are different manufacturers, Belkin for example may be four times the price but in general they are better quality and they also provide a lifetime guarantee I think.
If you buy any USB 2.0 hub then it is backwards compatible with USB 1.1. Same thing goes if you have USB 2.0 and buy a USB 1.1 hub, it will work but only at USB 1.1 speeds which are about a tenth of USB 2.0.
Powered hubs, it really depends on two things, how many USB devices you are using at the same time and how much power each of them use, ie are the devices powered from the USB or do they have there own power source.
I would buy a USB 2.0 hub, with a power supply, if you don't need the power supply then don't use it but its always there if you need it.
May I suggest something like this click here if you don't want a powered one click here