It is possible to join without a ton of grammar knowledge if you’re willing to do a lot of googling and asking of questions. When I joined the ABBC for Teasing Master Takagi-san I didn’t know a ton of grammar but thanks to the patience of the others in the club and a lot of googling I managed to muddle through (though to be fair I was continuing to read through articles on Imabi in that time too, so that certainly helped as I continued)
Also, I can’t comment on your financial situation, but a digital copy of the volume should work out pretty cheap overall (it often ends up being a lot cheaper than digital manga in English in my experience). Also as a general tip, Bookwalker frequently has free volumes of manga available (there’s the BookWalker Freebies Thread to help you find what’s free) - definitely worth looking out for as you can build up quite the collection just by grabbing free stuff