For my money, anything by Matthew Sweeney, Molly Peacock or Robert Minhinnick that you can get your hands on. I too don't really have the money to buy many collections atm. But search Google and you'll find a lot of good stuff.
Also, some anthologies are a great buy. I'd seriously recommend the Staying Alive collection.
Ah thank you! I gave a quick look and seems like some great variety. Will get to reading some of them by the end of the Summer I hope :3