If you would like high positions for a very long time without having to spend alot of money then gambling.com is the best PPC engine out there. Although you will not receive many (if any) clicks your listings will stay active for a long time.
I currently have two keyphrases online. One with a current cost of $4/click. The other with a cost of $0.36/click. So far I have spent less than $5 after a few months of advertising.