Download Files Pricing

Hello, I have just joined the Grinners are Winners team. I am currently setting up my Smugmug website with the hopeful intention of selling some of my photographs. I would like these to be downloadable rather than printed. I am not a professional photographer, merely a very keen learner of 2 years experience, so my images aren't as eye popping as some I have already seen on this site. Does anyone out there have any suggestions regarding pricing for .3mp; 1mp, 4mp and the original size of 24mpixel. I would love to make some money so I can keep purchasing photography equipment, but know I won't get rich doing what I love just yet, so keen to set reasonable prices but not give aways! Many thanks for any feedback. Have a great day - Glenda :) (it would appear my original discussion wasn't done correctly.... learning the hard way as usual!)