Regardless of whether you use your ISP's provided e-mail address or not, if you post a live e-mail address on websites you will get spam because of something called spambots which harvest e-mail addresses. If you need to post your e-mail address, break it somehow so it isn't live. Example: instead of email@example.com (I just invented this address for example purposes: it isn't real) you could write it like this:
foaming AT shampoo dot suds
By the way, I use my ISP provided e-mail, and I DO NOT get spam on it. I have in the past used e-mail that wasn't provided by my ISP, in fact I didn't have one or a computer, and got lots of spam because of my ignorance about not posting my e-mail address on the web and because I was ignorant about not
clicking on the "unsubscribe" link.
Another spam prevention: If you don't recognize the sender - don't open it - period. Do not allow images in messages no matter who they are from. Have your friends send images as attachments, save them to a file, scan them, then open them in your picture viewing software if they are clean.