You should really sit down with your intructor and have a frank talk with him about costs. You need to find out:
- what his "per dance" fee is to dance with you at the events
- what surcharges his studio will add to the price to make up for "lost wages" for being at the competition with you rather than back in the studio teaching (some teachers charge for this, others do not)
- what the entry fees are typically for competitions in your area
- what the admission ticket prices are typically for competitions in your area
- what other things are you "expected" to pay for, like banquet dinners, tickets to sessions you are not competing in, etc
- if you are expected to help pay for teacher's travel expenses, and if so, how much
- what is expected of you costume-wise (costume prices are extraordinary, look through the classified ads on this web site to get an idea of the costs of buying a used dress)
- also factor in things like make-up (gotta have good makeup, buy highly pigmented brands like MAC, stay away from cheap drugstore stuff), hair (either learn how to do your own or pay to have someone else do it), tanning (everyone fake tans, usually through various self-tanning creams), shoes (you can't wear your practice shoes in a comp, you have to have nice clean ones appropriate for your style of dance), costume jewelry (you just can't go out there without it)
It's not cheap, let me tell you. Even if you save money by competing in amateur events with a peer partner rather than dancing with your teacher, it's still not cheap.