I have a few suggestions as I always do lol.
Spyderco Resilience - huge tough and cheap
Even the Tenacious is great but if you want BIG go for the Resilience.
Spyderco Manix 2 - add $5 to your limit and just buy it - big, good for hard use, nice blade steel, sweet locking mechanism, etc. I love the Manix 2.
Kershaw JYD II - it's a BEAST of a knife.
The Cold Steel Recon 1 or American Lawman would work as well.
The Ontario Rat-1 is a good knife but really I'd go with one of the others.
Too bad you can't afford a ZT. Or you could save a little more and grab a ZT 0200 - you can pick them up cheap off of the exchange especially but other places have awesome prices as well. I really would just save up the extra money and pick this up.