Generators can definitely get spendy. Despite that, try hard to get an inverter model, and then (in my opinion) go for more gen that you will need, or at least select a model that can be paralleled to another later. I don't think you need to go for a Honda or Yamaha to get a good one. Once again, just my opinion.
Too much budget-mindedness often costs more in the long run, once you realize the cheap gen you bought is also way too loud to tolerate for more than a few minutes. There are budget minded gens out there that also provide clean power at reduced decibels. A lot of your decision should be based on what you need this generator to do. Just charge your battery(s)? You may get by with a small 1000 watt model. Run the air conditioner, you will likely want closer to 3000 watts. Decisions decisions :)