The cost of incorporating in the UK is cheap but you're creating a legal entity so there's more to it than just coming up with a name and parting with the cash. I'd have a read of the following to get an idea of what it entails and what other options you have:

https://www.gov.uk/business-legal-structures/overview

Most people won't care if its made by a person or company, as long as it solves their problem.

There are plenty of apps that are run by solo founder...I think you're thinking into it too much...always better to save as much money as you can and put it into the product at first.