Fly fishing is very easy to buy into with some money, very hard to catch anything though if you don't know what you're doing.
If you get the knack and learn from your 'failures' suddenly the fish are popping up everywhere.
I have got out of date on Adwords so can't offer any help. I would however suggest Facebook advertising is a better start for most. Just remember to read their TOS if you get banned you are banned and that's it for your FB account for life!