Hm well. I can give you some advice depending on what you are wanting to get. Up to 500mW lazerer.com is the best choice, but it will cost more than this laser above.
But there you will get a up to spec laser and for $2 more a certificate too.
You can also try o-like with it´s 500mW lasers, but there it´s more like playing a lottery. You may be a lucky one getting a on spec or even overspec laser, or you can get a underspec laser and will have to pay the costs to send it back in such a case.
They are a bit cheaper at o-like but when sending it back, it can turn into a more expencive task than buying directly at lazerer.
Looking for a even more powerfull laser there are other trustable companies, but again. This will cost a lot more.
Just forget about all the cheap offers out there. They all are fakes. You simply get what you paid for.
In the other hand buying an expencive laser is no warranty it´s up to specs. Only if buying it at the few trustable companies out there, you will get a up to spec laser.
You can also take a look at the buy&sell corner in this forum. There are a lot trustable members selling their metered lasers.