I kinda know it means v.a.t value added tax what i am getting at is for

example> £200 plus vat does this mean the total cost is £200 or does

this mean that the price is more like £230 @ a rate of 15% v.a.t. ??
You have guessed correctly.
If a mechanic says he will fix your car for £100 plus VAT, he will invoice you for £115. What he is saying in effect is, that he wants to make £100 and he will pass the 15% VAT onto the government. He will then have to put the £100 into his accounts and pay income tax on it.
OR he might say, it will cost £100 off the books. He will get the entire £100 and the government will get nothing. Although this is illegal, it is widely practiced. It is also known as the " Black Economy "
Plus vat means add it on so yes £200 plus vat is £230

The happy chappy your maths is wrong £200 minus VAT is £173.91. Get you calculator out and add 15% to 173.91.
You can add 15% in vat to a number but you don't minus 15% off a price including vat otherwise you are removing VAT from the VAT aswell
Plus VAT is just what it says amount stated plus VAT Rate (currently 15%) - so your calculation of total cost price = £230 is correct.
Value Added Tax A type of sales tax