new user

Just got my 80cc engine mounted to my Hardrock Specialized Trail-bike! It was a bit challenging to put together, but it's all worth it. I did mess up on cutting the chain, so I had to order a new one, but thankfully my neighbor had a proper chain cutting tool that he uses for his Kawasaki...

I am looking to buy my first bicycle engine kit for my bicycle. I have been doing lots of research but I want to know what the best kit for $250 or under, including shipping is. I know I want a chain drive engine. Please help. Thank you.