Please excuse the double post but putting it under "Electric Stuff" may have been the wrong place.
I used to make my own by printing the artwork, transferring them onto the actual board with ultraviolet light and then etching them in ferric chloride.
Now I use JLCPCB, yes they are in China and the shipping can take a while but they charge $2 for five 100mm x 100mm boards !
The last batch that I ordered were 22.5 x 25 which I paneled 4x4 to give 100 x 90 area, this gave me 80 pcb's !
Standard shipping is about a fiver and takes around 10 to 14 days, pay an extra tenner and have DHL do the honors, I ordered Sunday evening, boards were finished by the end of Monday and DHL delivered them on Thursday !
You can upload the Gerber file directly or use Easyeda which has import options for the most popular PCB design software such as Eagle, etc, or use it to design a PCB from scratch