Wetsuits have come a long way and at the end of the day, you are going to pay for that. Companies have spent endless hours in research and developing their materials so the cost of your wetsuit inevitably reflects this.
Eco-friendly wetsuits are always going to cost you more, but if that’s important to you then it shouldn’t matter. For a quality full body wetsuit that is going to last you at least two years, you’re likely going to be looking around the $300-400 mark.