Good for you I just finished replacing a set for a guy I wrk wth, 24 y/o and he can't change his own strings...oh well, we gave me $50USD for it...:-)
$50.00 to change a set of strings??? That is insane, that dude obviously has a bunch of money lying around that he can't figure out what to do with, I would say $10.00 is a fair price for re-stringing a six string and a little more for a twelve, because twelve strings can be a pain to re-string.
Well I took it to a music shop (a different one from where i got the origional strings) he took one look at the new strings and said...
"These are the worst quality strings I've ever seen"
I used to break a lot of strings way back, I tried all the top brands and broke them all, finally I tried Ernie Ball Blue Steels and have used them ever since, never once have I broke one of these strings no matter how light the guage, and I used them for probably 10 years when I was playing daily, I always played quite heavy music with lots of solo's, so I was pretty rough on strings, but the Blue Steels never let me down.
My stringing was not the problem, it snapped on a bit of rust.
Any little burr or snag on your bridge or tuning pegs will cause strings to break, every time you re-string you should closely inspect every area the strings make contact with and be sure there is a good smooth surface for them to set on.
Still no linked images allowed around here Paz! Naughty...