Exercise Equipment - Recommendation for adjustable dumbbells?

I'm looking to purchase adjustable dumbbells so I can increase the weight without having to buy new equipment. I've looked at several different products and the price is all over the chart - from $50 to $900.

Anyone have a recommendation for a good set (that doesn't cost more than rent)?

TIA

Depends how much your rent is :) I researched this not too long ago and I ended up buying the power blocks. I think they are more stable and don't have the risk of plates falling out like other systems do.

Those are definitely at the higher end of the price scale. Are they worth it? What makes them better than the cheaper ones?

The thing that worried me about the cheaper ones was the danger of plates falling. I read various reviews of ones that are 'dial' adjustable and many people said after a few months, it wasn't unusual to have a plate fall. Now personally, I rather not risk that with the weight over my head. The powerblocks are also more compact than many of the other adjustables.

I'll check them out at a sporting goods store. Thanks for the recommendation!