Easy part is you want the various Manchester parlours then. Not the massage places, but places like Sheridans, Roses, Temptations and Boudoir Babes all have £40 or less blow and go or 15 minute rates advertised.
Hard part is if you aren't a complete bell end, then after enjoying one of their £40 or less services you could ask reception if they offer a budget wank and go service. Hopefully you were a gentleman during your booking and came quickly and easily in 5 or 10 minutes. If so, they may be inclined to agree a reduced rate for a reduced and easy service. You might need to go a few times at the stated rate first. The idea with parlours is you can build rapport with the receptionist who gets to know you and remembers you and they will then find you a WG working with them on the day that is interested in your quick and easy business.
If you require 15 minutes of furious non stop wanking to reach an orgasm then they won't be interested in a reduced rate.
If you are demanding about getting all their kit off or wanting to do too much outside of the wank, lick this part of the WG, finger that part of the WG, "can you sing Baa Baa Black Sheep while wanking me?" then they won't be interested in a reduced rate.
If you are flexible on time, "sure, I can wait five minutes" and are flexible on which WG on the rota they use that will help with their interest in a reduced rate.
Harder part is some of the other Manchester parlours don't advertise, but do actually do 15 or 20 minute rates. I honestly can't quite remember which parlours so I don't want to throw out the names, but anywhere doing 30 minutes for £50 or less might be willing and do consider the more down market parlours that don't have websites. I'm not sure how well it would work to phone around asking or whether you need to be there in person. I would again look to build rapport with the receptionist while using their cheapest service, in the room be a gentleman, don't be a twat, then ask if they would offer a cheaper shorter limited service.
I'm pretty sure a well mannered punter capable of communicating their needs in a coherent manner could find a parlour to visit regularly for either a £20 or £25 10 minute wank and go.