well, on my subs (I have 2 "new" larger subs) I replaced the stock binding posts with another pair I got from parts express that are longer and threaded so no soldering was required and I could use spades on the end of the wires (the posts are about $60per pair). I then wired the inside with analysis plus oval 12 cable. What a difference this makes! The bass hits so hard and is soooo smooth, you will wonder how you listened to it before! I also use the oval 12 cable from my amps to my subs. This made it sound even better. You don't have to use both mods to hear an incredible sound difference, because you said you are on a budget. But if you can do both, do both. The cable from the amp to the sub itself would be alot easier for you to do and would cost about $300 (for 15 feet).
To do the mods inside the sub is labor intensive, and a second person makes it alot easier. You would need about 3-4 feet of oval 12, gold plated spades, and the gold plated binding posts. Total cost, about $200, if not less. You could contact analysis plus and they could make you a set of cables for the inside of the sub, so all you would have to do is install them. I don't know if this is to expensive for you, but this is well worth the price.
