Another what to charge question

Some friends have been asking me to help them with some resizing of jewelry shots and to take some photos of their booth to be juried for some shows.
I thought the resizing would be easy but I had to work on it a few times to get it right.
The Zapplication standards had be gridding some shots and counting the little squares to get the photo square as required until they brought over some instructions on how its supposed to be done and now its easy.
They don't have any photo editing programs and really aren't interested in working on the stuff, though they have been taking pretty good shots with a light tent..
They said they used to pay someone $1 per edit and now that its getting to be more I think that's a fair price to charge.
They also want me to take some shots for them, which will require a learning curve for me as I have done very little macro work but will know by looking when it is right.
I don't know what I should charge for taking these macros of their jewelry. The stuff they sell is about the size of a bracelet but also will want me to shoot some detailed shots of some charms which are about dime sized.
Any idea what I should charge for this kind of photo?

Anybody???