Gday Dailybean and welcome to the forum.
When you say a tight budget, how tight are you talking about?
Do you home roast?
If not, this would be the next logical step for use with your plungers. You can start off with a small investment of around $20-30 for a popcorn popper, some green beans from this site, and bobs your uncle. Great tasting, fresh (in every sense of the word) coffee :)
I dont have any experience with the Presso, however quite a few CSs do and report good results. Do a search of this site for presso and you should come up trumps.
All the best.