Try a Merkur adjustable or slant
Well, I'm no expert and it sounds like you'll be buying anyway, but here goes...
If the DE doesn't seem as aggressive as the straight, that's because DE's aren't as aggressive. With a DE, you can expect to take more passes of beard reduction to get the same effect as 1-2 passes with a straight.
If you want to get a more aggressive DE for under $50, I might suggest the Merkur Futur adjustable, which can be found for right around $50 on the B&B buy/sell/trade (b/s/t) forum if you look a bit. If you really want to get aggressive, you can also look for the Merkur 39C "slanthammer." It's a slant so it may present a bit of a curve in getting used to it but it delivers mightily in the aggression department. The 39C can also be found for under $50 on B&B b/s/t forum.