For sport parlays I like sportingbet, especially for the NRL.
Easy to use. Not sure about the prices but being a small punter that really doesn't bother me.
Simple system for the NRL. Pick a tipster from the paper to follow, then start by covering all the games with three 3 leg parlays. If you get something up then increase to more legs or larger bet the following week.
Only costs around $300 for the entire season and every chance of a profit if luck is with you.
We only got one 6 legger up last year, but that paid $250+ so a profit for the year was pretty easy when you take in the other returns.
Reason my son and myself try this is that we don't have to wait for either one of us to ring our tips thru. Secret is to pick the right tipster from the paper but it also easier than having to be on the ball and this way you have someone else to blame if you lose. Apart from the ref