Rebecca you've had what, 3 threads about this now? Obviously this is not gunna go away unless you really lay down the law with her. I think you need to show her some tough love.

And as far as random guys coming over, thats completely inappropriate imo. That sounds really sketchy and if you have expensive stuff in the house then you have every right to refuse to let that happen. Has your sister ever heard of the craigslist killer? Why cant the guy just take her out for a date? It actually sounds kinda weird tbh. Ive never gone to a chicks house and been like "nah, lets not go out. Lets just stay here instead." I would feel awkward not knowing her very well and having to meet her family right away. Id also feel like i was imposing. If the guys are too cheap to even take her out to dinner first then she needs some higher standards!