The electricity cost on that would be higher than just buying hosting.
Godaddy has web hosting for like a dollar a month if you get 12 months (Code CJCNI1HOS). There's some super cheap ones on lowendbox.com as well where you can roll like $0.50/year hosting, although the providers are smaller and may be more unreliable.
I think eBay gives you like 8 photos free per listing or something similar as well.