rust problems

[missluwanda.livejournal.com]

i've really gotten into decorating tins lately, but they have a havit of rusting once either paint or mod podge hits them. i was thinking maybe something like a primer would help, but i don't want anything a) too expensive or b) too fumy. i do most of my crafting projects in my bedroom and well, march in jersey is not a nice time to be opening the windows for ventilation. any suggestions on a primer that is either clear or flat white that may help my predicament? mucho thanks!