So I'm having trouble with this whole bitcoin thing. So say what I wanted to buy was worth $300 USD and the transaction were to be paid with bitcoins. The current rate is about $621 for 1 bitcoin; when I trade said $300 using localbitcoins.com for bitcoins, I get a decimal. I know the price for each bitcoin fluctuates often so my question is if that $300 in coins were given to the seller, would it still hold a value of $300?