Avoid the canister, like the previous commenter stated, they're great for fresh and not so great for salt. I've tried both an Eheim and a Rena (that were both significantly more than $60), and have quit using both of them. Look for a cheap used overflow or a new cheap one on ebay. Get a $10 10 gallon from Wal-Mart and toss the best skimmer you can find/fit in there. You'll eventually upgrade the skimmer if you stay in the hobby, but anything is better than nothing. The sump is truly the way to go. It gives you tons of options and gives that mad scientist in you some room to work.
I agree on the live rock and flow. Scrounge for some powerheads, but don't cram too much rock in there.
Use that $60 bucks for progress toward your sump setup. You can't solve your problem with $60, but you can come up with a plan and work toward your goal.
If you're concerned about filtration, don't add any more livestock and feed less until you get a workable setup.