I would disagree with going cheap. Which is a gamble to be honest. You might spend a lot of money on a good set only to find out that you don't like it. BUT, a GOOD set can make the difference between enjoying the rollers and hating them.

I bought a really cheap (quality and financial) set and it made my first perception of rollers not good. They weren't smooth at all and one of the drums had a slight flat spot which created a vibration. I just assumed this was how it was supposed to be. I sold that set after 3 months and only a couple sessions. I didn't ride on rollers again for 3 years. A friend of mine had a nice set that they weren't using and let me use them. The bearings were super smooth and the cylinders were true. Made a HUGE difference. I used those for 3 months and almost 3-5 times a week. I ended up buying a set of Tacx Galaxia rollers which are very smooth and quiet. They also have the rockers on the bottom which help take away the inertia while riding on them.

That being said, invest in at least a mid grade set of rollers instead of trying to get the cheapest set of rollers you can. Better to get a good set that will set you up for enjoying them and be able to sell them and make back some of the money rather than get a cheap set that nobody will want to buy of you end up wanting to sell them.