You could try Realm Crafter -- you're unlikely to ever make a big successful MMORPG with it, but if you just want to make an online RPG you can play with a few people as a hobby it would be a nice easy-to-use option with an up-front purchase price.
BigWorld is a more capable product, but you pay an annual subscription, which seems to conflict with what you want.
HeroEngine is probably the most capable option that's suitable for what you're after, but again it's based on a subscription -- at $99 per year it's pretty affordable though.
You could also take a look at Multiverse, which is free and open-sourced, but I'm not really familiar with it's capabilities, so you would need to do your own investigation.
There are also some "MMO kits" available for Unity that might be an option, but I don't know anything about them, so again you would need to do your own research.
One last possibility I can think of would be the sourcecode for Ryzom.
I'd really suggest that if you're after a hobby project and you aren't willing to spend much that you should reconsider approaching any sort of MMORPG however. With hard work and the right tools it is possible for a hobbyist or indie developer to create a fun online game, but it's not something that's typically possible in erratic bursts of free time. For a part-time hobby project I'd really suggest a smaller, possibly single-player game, or perhaps something playable in the web-browser.
Hope that's helpful!
oh yeah thats helpful.
I will take a look at the engines you linked.
99 dollar per year on heroengine isnt too bad really.. will think about.
Reason I dont like paying money specially subscription is because it kinda makes you stressed and feel like you need to put it more time to get money worth.
And because i also know that the game has high chance of failing totally and even if it becomes a success it probably wont make much money at all.
So this makes me not want to have to pay too much upfront but 99 dollar per year is possibly ok.
Can you tell me more about realm crafter?
it looks really nice at first glance on their website.
Why do you think its unlikely to create a big successful mmorpg with it?
They say on their website it's possible to make your mmorpg as unique as you want and that its a mmo engine
i been reading some reviews and realm crafter isnt for me it has real problems handling "larger" amount of players.. its not really a mmorpg just morpg lol
I still like to keep my options open incase it would turn out to a good game.
going to look into multiverse now