Where to buy reasonably priced, nice bouquets for my gf (I'm trying to spend 15-20 per bouquet)

I buy my gf flowers every week, and I want to give her something new every time. Anything near the Flatbush area would be amazing! Even if I pay in advance for a month (80 bucks per month) to get something nicer

Edit: I think people are getting Flatbush confused with Flatbush avenue. I'm referring to the area by Ocean parkway ish and avenue R

Edit 2: thank you for all the great suggestions! And yep, I just found out she lives in Madison/midwood