I don't think the charging port would be the issue here, but it does sound like it has been around the block a few times, more and more from your descriptions.
At this point, I'd be likely to counsel a new device. The reasons for that are several. As a new vaper, you do not want the headaches surrounding getting accustomed to your new vape and then having it break without vendor and warranty support. From the sounds of things you will have to source/part out many new things and that can add up, it's also more research and more difficulty and you may not really wind up "saving money" in the long run, especially if there is some tedious but as yet unknown problem with THIS one.
Finally, if you seriously want to try vaping as a substitute for cigarettes, the last thing you want to have happen is for it to fail, and you are left with needing an extremely rapid "new vape" or "repair/warranty" which you won't be able to do with this one.
Really, once vaping is working for you, you need a backup for if something goes wrong with your primary setup and whatnot, so if you do buy THIS one, I'd make good and sure it is actually working then keep it as a backup if the price is genuinely right. However, once a mod has been purchased by someone ELSE they can certainly TELL you "how they were using it" but that information isn't always accurate and also cannot really be verified..
I might go with your gut on this one and buy new. Vaping isn't a game of "go fish" and frankly the more you can get with a new mod (vendor support, a warranty) the better especially as a new vaper.
Anna