If you really have no idea how mIRC scripts work,
of course you would need guidance.
Chezor, although it is right to some extent that you can learn by studying scripts on your own, you do not need to say that every single time someone asks for help.
My best advice to you, gta5 is that you join GTAnet and ask for help from several people. Some would be helpful enough to provide you with short example scripts and such. Just don't forget that people are not robots and that you should not spam them with "Are you there?" "HELP ME PLZ!" and etc
An alternative way would be to edit the script on your own.
A buycar script cannot be easily done by a newbie.
You can't get an A+ in quantum mechanics without having learnt basic kinematics and wave properties. Try and edit your script as much as possible instead of trying to make a buycar script.
On another note... why do you even want a buycar script?
It's pointless to have one since almost every server has it.
Sorry for the overly long post. Just hope it helps.