ok, well...pictures are cheap to add. Ebay charges a listing fee (they call it an "insertion fee" - you should like that), then a "final valuation fee" at the end of the auction.
Listing fees depend on number of pictures, other features (bold, gallery, buy it now oprtion, etc.). Listing fee also depends on what your starting bid is. The higher the starting bid, the higher the listing fee (highest is $4.80 - this does NOT include add ons). Ebay lists their fees on their site.
Final valuation fee depends on what your item actually sells for. highest possible is: 5.25% of the initial $25.00 ($1.31), plus 3.25% of the initial $25.01 - $1,000.00 ($31.69), plus 1.50% of the remaining closing value balance ($1000.01 - closing value).
Then paypal takes fees too (or whatever other payment system you use (bidpay, etc.).
That's a whole other deal. I think I used to just average out 10% for fees. Incidently, 10% is what an auction house typically charges you to sell your item(s).