Some people haven't mentioned everything with Tribot so I'll give you a *tiny* rundown of what to expect:
Paying for VIP gets you access to all of their free scripts - you can use them on as many accounts as you want simultaneously.
Paying for VIP extended (about $1.50 more, from memory) will give you access to proxies (plus some other things, but essentially proxies is the point behind it). This will mask you IP when you connect - it's only really important if you want to goldfarm and don't want to delve into a VPN. It seems like you're just botting up a single account, so I wouldn't worry about this
AND THEN, on top of this there are premium scripts. You can expect these scripts to generally be better / hopefully flawless, so that you can run them without baby sitting. I'm not going to lie, the free scripts are usually quite great, but if you want something guaranteed to be stable, premium scripts are the way to go. They do cost extra, and the costing varies. Some scripters will charge on a per month basis (ie you have access for 1 month only), some charge on a per instance basis or per auth, meaning you can only use it on one account at a time.
Really, just look at what you want. There are some great scripts out there for free, and the tribot client is extremely stable itself and rarely fails randoms (I haven't to date, but some people do report it failing). If you plan on botting overnight, for example, you might want to look into premium scripts, otherwise the freebies will be pretty sufficient if you just read the threads to know which ones are stable and which are outdated
Happy botting, good sir!