If you're using master-master replication, you need to take a few extra steps to ensure your application will work correctly. Locking is very important for a master-master setup otherwise you can end up clobbering data or getting transient errors due to conflicting primary keys.MySQL master-master configuration is probably what you are seeking.
Here's an old tutorial:
http://www.howtoforge.com/mysql_master_master_replication
I already have a vps host
And
By paid I mean . Pay users just like adfly but with better payout options
I have to agree. Something like this will take quite a bit of $$ just to lift it off the ground, and I don't know how well it will be received by consumers.You're going to need more than 'better payout options' to compete with something like adfly. Personally I won't even click an adfly link, and I'm willing to say most people on this forum share the same feelings about it.