440a is a good steel for a budget knife. As others have stated, the edge retention is not as good as other steels, but it does take a pretty good edge pretty quickly. Frequent touch ups will keep it sharp. Perhaps the most important thing as far as I'm concerned is to get a knife with this steel from a quality company. Since this steel us used so frequently in budget knives it is common to see a cheap knife in 440a with a horrible factory edge. Unless you plan on putting a new edge on your knife, get one from a company that has a good reputation and puts on a good edge from the factory. I'm personally partial to Kershaw for relatively inexpensive knives, but there are a lot of good choices out there.
Recently I upped my knife budget and started buying in the $100-$150 range, which really opens up your options to great knives with great steels.