I'd say I only spend about $5 on an average wash in quarters. That would mean I would need to go more than 40 times to break even. Some take longer, so maybe you'd only need to go 30 times, but still...
What do you have to lose? Well, say you go 10 times in a year... then you've given away over $100 for nothing
Say you go 40 times... you could have kept the money and paid as you went rather than giving it all in advance
Say you go 60 times and save a little money... Is it worth chancing that you might NOT go nearly every week?
That's a really good deal, especially if you are an obsessive compulsive like me.
I spend about $6 almost each week on the self serve car wash.
For that deal I could give my car a quickie rinse a couple times a week, especially in the winter season when all kinds of snow melting chemicals are sprayed all over the roads.
The vac is also a plus too.
You could also pass your key to your friends in exchange for beers!
I use either a touchless or the coin op almost exclusively now. Not becasue I like to, but unfortunatley the storm drains dump directly in the lagoon behind my house ... the junk coming off the car is not good!