Is there a cheaper way of getting the other 7's dob's, etc without paying on SP?
There's no way of getting certificates without someone paying something to SP.
You could try
http://www.sctbdm.com/index.php but they only have tiny proportion of what is available. It relies on people who have paid for certificates providing the details.
Some people who have put trees online have added copies of certificates bought from SP, even though this is in breach of copyright. Again, the chances of someone having done this with one the certificates you want is very small unless they are researching the same family.
The cheapest way to get certificates is to go to the Scotland's People Centre in Edinburgh* for a day. You pay £15 and you can transcribe any certificate you like at no further charge, or print off pre-cutoff certificates (births over 100 years ago, marriages over 75 years ago, deaths over 50 years ago) for a small additional charge - I think it's about 30p per certificate.
*Or Glasgow, Inverness and Hawick, though their opening times may be shorter than Edinburgh's.
If you can't get to Edinburgh, you could hire a professional searcher to find and transcribe or print off the certificates you want. This might be cheaper than downloading the images, depending on what the searcher charges.
At £1.50 per certificate, they are much cheaper than English ones (£6) and a lot cheaper than certificates in most other countries.