Suggestions for a surprise/gift for my DH?

My DH is turning 30 in August, and he's getting his PhD in May. Our anniversary is in June. I'm thinking of getting him a separate anniversary gift for the 2nd anniversary (something small). But I want to get a bigger, combined gift for his 30th and his graduation. Money is tight though, and I really can't spend more than $300-$500. Any suggestions for this price range? As is, this is going to be hard and I'm going to have to save a LOT. But I don't want to not do anything because its a really special time for him. If we could do a trip to celebrate everything, that would be good, but for $300? Any suggestions? Non-trip ideas also welcome and very appreciated!