Purchased email lists are a no-go for several reasons. Firstly, the contacts contained within a bought list are unlikely to have opted in, which violates several data privacy laws. Secondly, a reputable email provider won’t allow you to use purchased lists for that very reason.
Finally, purchased lists usually contain poor contacts, with seldom-used or very old email addresses that are likely to bounce anyway. The best approach to email marketing is to grow your list organically; you’ll end up with a much more valuable subscriber list this way.