$6 is really cheap. I dunno if that is the case cause you're in a cheaper region or if it's because the person doing it is inexperienced and charging a smaller price for that reason. A typical store around here would charge at least $12-$15 for a Senegal if not $20. A vet doing it could easily run $50-$100. So if things in general cost less in your area than mine, don't freak out but if you live in a pricier neighborhood, watch out that someone charging less could be inexperienced. Basically learn everything you can about how it should be done before you go and then make sure they are doing that.
I suggest all parrot owners
know how to clip their parrot's nails (wings if applicable) but that they don't do it themselves and have a pro do it. By knowing, you can make sure they are doing it right and also know what to do in an emergency. However, actually doing it is harder than it looks and causes a lot of stress. So I don't recommend that you (and most parrot owners) do it themselves.
Here is a post (with videos) about how I did it. Keep in mind that I'm a total newb at cutting nails and have only done it a few times myself. I'm doing it right but just taking my time and being really careful. A seasoned pro can do it in a minute with no bites and no bleeding. My version is kind of a slow motion of what an experienced groomer would do. Just remember, I'm not suggesting you actually do it but if you know what to look for, you can watch the person cut someone else's bird before yours and if you are comfortable with them doing it, $6 is a fantastic bargain for all the biting and trouble cutting nails is