I don´t think the 99.99999% closed ports is real. Many ISP´s just give you a plan, like x $ for x bandwith/speed, so that may not be the problem. And though port 80 is nice to have for url working corectly, well, there are other ports...
I would sugest a one click free server like abyss x1, a registration at no-ip.com for a free nice url with support for dinamic ip, and you´re ready to go!
now, 3 simple tips to have it working...smothly...
Hot-link images and media content stored in some place,(the space your ISP gives you, for ex: or your site will not run and open in decent times.) and compress images the most you can. In reality, compress everthing the most you can.
the all website starting page for a 512 kbps up-stream MUST not be greater than 30, 50 k at the maximum, or just forget it...clean the code, as many sites have some 60 k in size when created, and after cleaned, they get a nice 8k, 10 k html file. This is crucial.
To be considered a server you must have your PC on all the time, and monitor it daily, checking log files to see your visitors and hacking atempts, otherways, forget it. Just restart some times when the thing crashes or you notice it is slow and un-responsive.
You´ll have lot´s of fun, until you realise you must come here again to freewebspace to have a taste of the real thing
anyway, go ahead!. It is fun and a true challenge, a home server.