£37.50 is the price of 1 adult and 1 child returns.
If you do a lot of journeys, consider a Family & Friends Railcard. That reduces the price to £21.25 for this journey, and all you need is to do a journey like this twice a year and you are saving money. Also if you travel on Virgin Trains (e.g. Wolves to London) you can use 'peak' time trains on off peak tickets, for example Wolves to Manchester at peak time is £220.50 for 1 adult and 1 child without a Railcard, but only £36.85 with a Railcard.
Also the ticket can be reduced in cost by splitting the journey into a combination of tickets.
If your trains call at Stoke:
Wolverhampton-Stoke Off Peak Day Return £16.65 (1 adult + 1 child, no railcard)
Stoke - Manchester Off Peak Day Return £17.70 (1 adult + 1 child, no railcard)
Total = £34.35
Further or alternative splits may be cheaper.