Hello
Newspapers are often the best source - I use Findmypast, but there is also the online newspaper archive. I'm not sure about this, but it seems to have some potential. To be in a jail on Stafford it seems likely that her crime was committed in Staffordshire. I have only found one Sarah Edwards.
The Staffordshire Sentinel 3 Jun 1878 p3 reports SUSPICIOUS. Sarah Edwards, hawker, was charged on remand on suspicion of stealing a wedding ring. However, it could not be found and she was released. This was in Hanley.
The same paper 8 Dec 1880 p6 reports that Sarah Edwards, having a previous conviction for stealing, was fined 20s and costs for stealing some coal. She did not pay so was sent to prison for 14 days. 20 shillings was money she could only dream about. A straight calculation based on inflation suggests this would be about £85 today, but it was much more in reality - in 1871 miners in North Staffs were only earning about that much per week, often 55 hours. At today's minimum wage of £6.50, 55 hours would pay £357.50.
The same paper 13 Aug 1880 p3 reports STEALING A PAIR OF BOOTS at Kidsgrove on 30 June. Sarah Edwards said she had 3 children and claimed that she had bought the boots from a Mrs Hankey, who was away. Sent for trial, remanded in custody 1 week to see in Mrs Hankey could be found.
The same paper on 15 Feb 1881 reports THEFT FROM THE PERSON of 2s 9d on 12 Feb at Kidsgrove. Sarah Edwards was found guilty and, having 3 previous convictions, sentenced to two months with hard labour. She would have been in prison on census night.
It all points towards your Sarah, but what was she doing in Kidsgrove and Hanley, and did she have 3 children in 1878?
I have found other people in a similar situation. They have no work and are forced to steal to survive. Eventually, they are caught and fined. They can't pay without stealing again and each time they are caught the penalty is more severe. One man I found was sentenced to 14 years transportation for stealing two geese, but he had a record as long as his arm.
Best wishes
Dion