An Island, the size of Gibraltar.

The biggest purchase I'd make online would probably be anything shy of a house or car. When you buy things online, the point is that it's convenient, cheaper, faster, or a combination of things. The problems with buying things like houses or cars, is that these are things you generally want to see in real life to get a feel for what they're like. To buy a house entirely online would be kind of a bad idea, because there's a lot of things you could miss. Now, I might use the Internet to direct me to houses I'm interested in, like, certain locations or sizes, but to do the entire procedure online would be difficult. So all in all, my limit for an online purchase probably is... anything, that I feel comfortable with buying based entirely off pictures and description alone. This also is affected by the reputation of the seller and other people's experiences, but if I go online, and I know I want a certain car, that I've drove before and liked, and I can go online to trusted site and get that exact car, I'd do it.