For reds, I rarely filter them - if they are pretty clear, that's usually good enough. For whites, though, they show haze pretty quickly. If you rack very carefully before bottling, and leave a bottle or two of wine in the carboy, you can probably bottle without filtering. (Save the last bit of wine from the carboy for use in cooking, or ???) A Buon Vino mini-jet is a couple hundred dollars, I think. And you go through a set of pads each time you use it, which is something like $3 to $5 per set, depending on where you get them. While not absolutely necessary, a filter is probably one of the first things you'll want to buy (new or used) when you get serious about winemaking. That and a really nice floor corker. That's my two cents.