Most server use Dvamp Interlude extender today, but its very unstable and got lots of work to even make it work properly. Can buy the extender for like 50-100USD and a complete server base for around 200-300USD. Best idea is to hire a coder to make you a extender but it will cost you alot of money. L2guard got Hellbound/Garcia extender for around 900euro with protection system this is imo the best extender out there that you can buy.