it will cost $50 (parts and labor) for the vacuum shop to..
My opinion on this, which the original poster can take as one wishes...
One has been a appliance/ vacuum repair person now for over 20 years...putting a replacement plug on a item such as a lamp for example, that does not require lots of fiddling with the cord or plug is FINE to a degree. Such an item is not drawing a ton of current, and it "can be" relatively safe...This even CAN apply to SOME other older appliances that draw lower amounts of power (amperage) such as early vacuums.
One would never want to do something like this on a toaster, coffeemaker, waffle iron etc (that draws a high amount of power), but it has been done for years. usually at the behest of a customer that wants cheap over the benefits of doing it RIGHT!!! Replacement plugs, from what one has learned in this business, were NEVER intended to be a proper fix, but a definite stop gap, until a new complete cord could be obtained.
One is not saying that it cannott work. It can. There are even youtube vids to prove such. In fact, most commercial vacuums I deal with, have the replacement plugs on them and work just fine. But they arent of MY doing. When your dealing with an oft used home appliance however, one is dealing with YOUR safety, YOUR home, or YOUR appliance....the actual dangers one can face over such a repair...is far more an issue/ liability than ponying up and just getting a complete cord assembly.
With that said, for US ...it IS a LIABILITY. Today, most repair shops of good caliber and conscious refuse to do such a fix.... In today's sue happy society, doing hack jobs, or even temp fixes are rife grounds for a lawsuit. Roll your eyes if one must.... BUT...it's happened and will continue to happen. It's just not worth it to a good repair center to take that liability anymore.
Cord assemblies are not all that expensive. And, knowing the amount you were quoted...is actually kinda on the low side...
Further explained...these replacement plugs on high draw (amperage) vacuums is potentially DANGEROUS on the account of the cord and plug on newer 12 amp machines draw high enough current which cause cords and plugs to "heat up", while in ise. If you take this into account, plus the constant twisting of the cord while in use, not to mention the occasional yanking of the cord, causes these "replacement"plugs" to separate from the cord causing a electrical pop/flash when it is yanked once too many times...electrocution, AND or fire.
If one couples that up with self-attempted hack jobs one sees, that are for the most part being improperly put on in the first place, or a combination of any of what I have said, seems to me to make A $50.00 repair not seem so pricey when it comes to the safety of the user and ones home and items. Then again people do things all the time that put themselves in jeopardy over lack of money/ wanting to spend any....
In summary...do what one wishes, but it seems far more logical for one to play it safe and just replace the whole cord. IN the long run, it's better to be safe than sorry. You may temporize, but it's like playing the lotto....for the most part, the gains are far FAR less than the losses you might incur...
Best of luck to you!!!