If you have another job...this can be a fun hobby that you can make money at...but make sure that you only take the jobs that are going to pay you instead of local festivals that are complete question marks. For example, find an alumni club at a local university and do caterings for football games for their alumni group.
Don't feel like you have to work all the time and if you can take a cooking class or a catering class from somebody like jbrink01 or Jacked Up...they'll take the fluff out of it and give you the real details and some tips on producing better bbq and making money when it is available.
I agree with what Matt said about purchasing...it's kind of like investing in anything...you make your money on the purchase. Choice briskets 1.89; Whole Chickens .89; Pork Butts 1.35; Spare Ribs 1.49 (all IBP except for the chicken).
Good luck and try to find select opportunities.