Check the lundy manor wine cellars its a beautiful spot and Erin the coordinator is amazing. I wanted to have my wedding there but it only held 90 ppl inside and I dont want an outdoor wedding, which is their main thing. Im not sure about pricing but worth to check out!
Niagara on the Lake is a nice area that is hard to find what you may want to consider. You choose to void out halls, wineries, restaurants and breweries out. The only place that seems to be left into consideration is a community center that has a small room that you can hold a welcome dinner. Park is also workable if you need to get in touch for getting the space and tent to pitch up with tables for food and bar.
Search for the best results of what you two really want to do and what resources can work towards your budget. Narrowing the choices down helps though the place may not be up to par for its atmosphere.
So many options! Are you looking for just a restaurant that can accommodate this many people? Or would you like a hall?
Personally Niagara on the lake is not going to be very low cost. Most places right on the Main Street are small, or will be pricey. You can check prince of Wales or even Queenston heights restaurant. Greek on portage (Niagara Falls) has a nice banquet area and good food. I’ve been here for many baby showers and retirement parties.