Seth Godin recently talked about people who begrudgingly agree to work together or perform a business transaction, spending an inordinate amount of time explaining how it's a special case that isn't going to happen again.
I have to agree with his point that it makes no sense to go half in.
Just recently I had my racquet restrung, since I've been playing quite a bit in the mornings before work. I went to a local retailer, who is often more expensive than chains, but whom I generally trust. I had been looking at their website and found some string for a good price. When I got to the store, they did not have the same string as what was listed on their website. The string in the store was all $20, whereas the online string was $7. I asked if they had the less expensive string I'd seen on their website. The guy helping me said they didn't, but that they price match anyone, as long as it is the same item.
I paid $20 for the string and left my racquet to be restrung. After I got home, I got to thinking about the price match policy I had been told about. I looked online and quickly found the same string I had just purchased for $4, plus $5 shipping. I called the store, confirmed they would match the $9 price, drove back to the store, and waited while everyone in the store complained about how the price was too good, how it was probably below their cost, and tried to figure out a way to not give me half my money back. They relented and gave me $11 in store credit, which I told them I'd use to buy a racquetball glove another day, since the store was just about to close.
After several days of calling to see if it was ready, I talked to someone who said they didn't want to string it for me. I would have been fine if they had told me up front the price match didn't apply, since the in-store purchase included the stringing service. In effect, it's really not the same product, which is why I specifically asked about that issue on the phone before I drove back in. Since they did initially agree to string it without charging any extra when I talked to them the first night, I finally convinced them to actually string my racquet.
My issue now is that I don't want to go back there again. I'll go use my store credit, which at their prices won't buy me much. I was planning on buying $100-150 worth of bike parts from them to fix up my bike or perhaps even buy a new bike. Now because of the big deal they made out of $11, I'll probably go somewhere else. They've made me feel guilty like I was trying to get away with something, and I feel like every cashier knows who I am and talks about me as soon as I leave.