I'm trying to do exactly that (embed a terminal, not make you pay for it) with https://github.com/wuub/SublimePTY, but the progress has slowed down to a stop lately because of humongous pileup at work.

You can also try SublimeREPL [https://github.com/wuub/SublimeREPL] / Shell for now, but it's good only for very basic stuff as SublimeREPL does not aim to be a terminal emulator at all.