Many people that come to Thailand feel like they are always trying to be ripped off.
Well that might be the case in the minority, however, the majority of Thai’s dealing with westerners are just trying to survive financially.
They have no formal education how to sell and try to get as much money as they can.
It is dishonest to ask 800 thb for something they will end up selling for 150thb?
Probably. Although the intent here is financial survival and they will use their instincts to make as much as they can.
You may be the only western customer they come across all day. If that is the case, they will try to make more.
Instead of malice, understand these people depend each and everyday on what ever they earn selling.
You are the intelligent one that can save no, or barter down to a price you are willing to pay.
When you look at the hardship of no social services to help out, it is hard to blame a person that can only survive on what he/she sells each day.
Some Thai seller’s have learned bad habits towards foreigners, but in the end, it is up to you to say no.
Don’t be offended, it is a way of life for many.