I’m a total novice to trials (had plenty of road and Mx bikes mind) and have a 2016 250 beta evo and it’s perfect for me. I’m not the lightest, tad under 16 stone.
The bikes super light and has more than enough power. Considering the age you are looking at I would buy on condition, I also agree look at the surroundings it’s coming from. I have a OCD and my bikes like new and kept in top condition, most people who see it thinks it’s never been used!