As athletes, we have to try to get the most for our money. Between the fitness gurus, the expensive gyms filled with "tough guys" sipping imported water and the plethora of just straight up bullshit that we get offered, it is often tough to sift good places from bad.
Well your buddy Zappa is going to help you get started.
For many of your general striking needs (bags, gloves, headgear, that kind of shit) I cannot recommend any other company other than Ringside. They simply piss on Title and Everlast products. They have nice ass gloves for both boxing and MMA. They sell standard bags, speed bags, double end bags, specialty MMA bags, you name it, they have it. And it is the best.
http://www.ringside.comFor you martial arts specific needs, I recommend a local company (for me anyway) called Karate Depot. Cheap ass prices and awesome equipment. They have weaponry, uniforms, and other training equipment. Definitely comparison shop with Ringside on certain items.
http://www.karatedepot.comResistance bands are underrated. Do some Good Mornings with a 200 lb band and tell me how bitch they are then.
A few good resources
http://www.elitefts.com elitefts is great for bands, but pricey on other shit. They have a lot of stuff though. Geared towards powerlifters.
http://www.ironwoodyfitness.comAnd then there is always homemade equipment.
I hope this helps, those four sites alone should get you most of what you need.