Yes... 680 is insanely expensive. Don't get me wrong, there are alternatives... Avery makes a decent removable reflective. Oracal does as well..both which are cheaper, the only problem is a lot of places spec 3M.Vehicles aren't my specialty so I just had to look up a 10yd 24 inch roll of that stuff just to see. Expensive is no exaggeration. $310...wow
You could also go the bubble free, non removable route... which a lot of places do. However when it comes time to repair a damaged vehicle, removing and re-applying graphics is a pain in the ass, or when they get rid of the vehicle after XX years and their policing decals need to come off... Another pain in the ass.
We don't usually buy the pre-colored 680, We buy the white and print everything for the police vehicles we do. A bit more expensive that way, but you're not bringing in 10 yards of 4-5 colors to match stripes / etc.
And yes, It can be lucrative. We were in OP's situation where they asked us to do one vehicle because they weren't happy with their old company - They loved it... and now we do 10-15 of their vehicles per year, ontop of 10-15 city vehicles... AND a huge (2 million pop) city is going to be re-branding and purchasing all new vehicles...Theyre estimating 50-100 vehicles to start. And we got put at the top of the list due to recommendation by the city we're currently doing work with. They asked us if we could do them all in 3 weeks and we turned them down and said no, it wasnt possible. I dont think theyve awarded the contract yet... But sometimes as much as it hurts, you need to turn down a job if you don't think you can meet their expectations. Badmouthing travels a lot faster and further than word of mouth does.
don't take on a job until you're ready to do it, otherwise you might be blowing your one and only chance!