Need an O-ring - Anybody ordering from anywhere???

Yesterday I changed the GFO in my Phosphate Reactor and somehow managed to lose the O-ring - so it leaks and can't use it at the moment.  I've checked the stores locally and can't find it - even tried True Value at Tim (Seascape's) suggestion.
Most online stores have it - and its only $1.49 - $1.99 - but shipping is all about $9.00.  So 1) if anyone has a spare o-ring lying around (3") that would be wonderful, or if anyone is placing an online order that I could add an o-ring to, that would be great.  Pleaseeeeeeeeeeee let me know.
Jeanette

 

Thanks for all the suggestions.  I'll try them.  I found an o-ring at home that was about an inch larger in diameter - and cut it to size (just a tiny fraction larger).  I'm using it right now so that I can run the skimmer and its not leaking, but I don't want that as a permanent solution - as I'm afraid that it might leak and then create a big mess.  Matt (Ninja) - I'll try these other places first, but if they don't pan out I might have you try at your work.  It is the o-ring, not the washer.  I think its a 3" diameter - but it could be slightly off from there.