Lots of good advice already given here Ancient.
As already said if you go to her bar every night you may have others pleading for drinks out of you , happened to me many times but if you don't want to be highly generous then you can either stay strong and just say no or make it clear you only buy other bg's the occasional drink , keep away from the bell unless you have money to burn
It's best to talk to the owner of the bar if you want to take her away completely , if her barfine is 200 per night you may be able to negotiate a better price with the owner for paying 1 or 2 weeks worth in advance.
so instead of 1,400 baht for 1 week , they may let her go for 1000 but depends on the bar owner and your negotiation skills.
One point to add here though, if you stay 1 or 2 weeks with 1 girl (which is something you may prefer) it is highly likely to turn out more costly than the butterfly way , you will invetiably buy her presents and take her shopping on top of the money you agree with her , on top of that there is other expenses to consider , food ,drinks etc...
Whereas if you take a new lady each night you can then choose if you want to dine alone or sometimes take a lady with you which is something many guys do and overall it will probably not cost quite so much.
Then there is the issue of ''me like you too mutt'' you may then be required to support her finacially from home via your bank account to hers as she nows claims to give up the bar for you and love only you.
It's up 2 u as they say :cheers: