...and generally you can expect to pay around $15 PER VISIT (mine gets 2 visits/day, so it really adds up). I went through 2 petsitting companies before I found a third one that I liked.
Even with a petsitter you trust, accidents can happen simply because she isn't used to your iguana's daily behavior. Bud lost half his tail when my trusted, competent petsitter grabbed at his posterior to prevent him from falling to the ground. Later I explained that it's better for him to fall on the ground then be caught by the tail. Unless you live with an ig, it's hard to know/remember everything.
My boyfriend now usually takes care of Bud when I'm away, and I try to thank him by taking him to the movies and out to dinner when I get back... although I feel that, for the care Bud gets from him, even the petsitter's fee would be too little. He's the best iguana sitter I think I'll ever find, because he's used to Bud, has taken care of him with me from the time I adopted him, and knows everything there is to know about iguanas.
If you have to find a professional, I've found that you can find out if they're doing the job right by having your roommated keep an eye on things one day (without commenting) or having a neighbor stop by at the same time to water the plants or something and then report to you what's happening.
This is how I found out that the first two sitters were doing things like picking Bud up from above and not giving him a bath. Things like this are good to know, because then you can work on that with the person. (The first two did not change what they were doing, even after I asked them to...)
When you find a petsitter you like, (whether a professional or a friend/relative) compensate them as generously as you POSSIBLY can. With a professional, this builds a good relationship where they're willing to follow your instructions even when it's inconvenient (vigilent tub-disinfecting, for example) and might even schedule you in on short notice. With friends and relatives... well, you know how hard it is to take care of your ig every day, and just think, they're doing it because they love you and your iguana.
And possibly because you'll take them to dinner and a movie. 