Bidets are those devices that spray water (and sometimes air) on your posterior. They are more hygienic than toilet paper, and save you money in the long run.
Bidets are very popular in Japan and parts of Europe. You can actually install a “bidet seat” quite easily, in place of your existing toilet seat. Bidet seats attach to the existing water supply through a double adapter and a hose. Some seats are quite elaborate, featuring jets of heated air, remote controls and various water massage settings.
A while back, we recommended Terry Love’s toilet reviews. He also hosts a good overview of bidets (but no reviews unfortunately). He does recommend the Toto Chloe and the Biobidet however (see this short reply to a reader). I’ve used a very basic $70 Biobidet for a year now and it works fine, if you don’t mind cold water.
There’s also hand-held travel bidets available.