Back when I decided to get fractional plates, I just decided to take the plunge and get the $50 Iron Woody set. The flexibility to increase by any amount between .5 and 4.5 (in half-pound increments) is quite useful, and it's something you can use for the rest of your lifting career (or at least as long as consistent 5-pound jumps aren't sustainable, which will be a while on stuff like OHP and isolation work). IMO, you should just save some money elsewhere, say by not buying some bogus supplement for a month, and get a decent set of microplates.