Travel Solo Price Difference

I think it will depend on where you are staying. If you stay in hotels in this country most now all have double rooms. To stay in a Premier Inn or Travlodge there is no difference in price for staying on your own.
If you are travelling abroad a lot of them will include a "single supplement" and this can be as much as two people travelling.

Have you looked at companies that specialise in single travel? Most of these offer good accommodation with no single supplement. It also means that you will have others around you if you don't want to travel on your own.

I have been on "singles" holidays a good few years ago now and they were really well organised and fun times away.