How big are the trees? (If trees of any size are involved, hire a "tree monkey".) Or is it just brush and small trees? Are you a DIY sort of guy? Do you know how to use a chainsaw? How fast do you want the job done?
You can hire a company to do this sort of work or you can clean it up yourself. If you hire the work done, make sure they have a business license and are carrying liability insurance. Sometimes, you can get the price down by having the yard company chip all the brush on sight and leaving it behind.
If you do it yourself, you will need a dumpster, lopping shears, work gloves, maybe a small chainsaw. Its not a difficult job, just a labor intensive job. Dumpsters are priced by number of days, how many times they need to be dumped, what's in them and weight. So, you only want to keep it for a couple days and you want to pack it well so you don't run out of space before you run out of job. "Green" dumpsters are cheaper because you can only put yard waste in them (no furniture, etc.).
Alternately, you can rent a chipper and make your very own mulch. Make sure the chipper is adequately sized for the job.