I have a date but a guitar I really want is on sale.
Are you going to go on the date anyway?
I'm going to ditch the date so I can get the guitar.
I understand you really wanting the guitar but you shouldn't cancel your date to get it. It would be extremely rude to do that. What you could try to do instead is incorporate getting the guitar into your date itinerary if getting it is really that important.
I'm gonna go to the shop and check if there are any more cheap guitars.
It's rude to ditch a date, especially at the last minute. I'm pretty sure you could figure out a way to do both, and then everyone can be happy.