[Thanks to Pat Storey on Northumbria list for this].
One of the improvements to the revised Scotland’s People website is that you can now search the indexes, including the Old Parochial Registers indexes, for free. It only costs you credits if you want to look at the actual records. You need to register to use the site but you can then look at the OPR, statutory registers, and will indexes etc.
If you are using the OPR indexes particularly, set the surname search option to phonetic and the forename to “names that begin with” (and depending on the name, don’t necessarily spell all of it, e.g. use “Is” for all the Isobel/Isabella variants or “Marg” for Margaret).
Web site address is: https://www.scotlandspeople.gov.uk/