"How much does a divorce cost?" is rather like asking how long is a piece of string. As others have said it depends on the amount of work involved. Sending an email will cost about 10% of the hourly rate. I'm not a solicitor but what people need to realize is that solicitors' fees cover the costs of accommodation, staff, training, IT, insurance etc. The cost of insurance alone isn't insignificant, typically it breaks down to about a third of the fee.
Costs can be kept down by doing as much work as possible between yourselves. The first thing is in Scotland all the assets (including pensions) held in joint and sole names need to be valued as of the date of separation. The Cash Equivalent Transfer Value that is given for pensions doesn't always reflect the true value and sometimes it is necessary to obtain an actuarial valuation that can cost a couple of thousand pounds. The value of the pension is apportioned according to the number of years contributions were made to the fund.
Then any non matrimonial property needs to be identified eg assets that were owned before marriage, gifted or inherited that have been kept separate from family finances.
Once the size of the matrimonial "pot" has been determined it is shared "fairly," usually equally although if a spouse has been advantaged or disadvantaged by the relationship (eg given up their career to care for children) or there are special circumstances moving away from 50:50 might be justified. The value of pensions apportioned to the marriage can be shared or offset against other assets.
There is no reason why you can't sort out the valuations and collect and copy documents yourselves ready to produce for the solicitors when required. Most people will need advice regarding the valuation of pensions. You can also negotiate an agreement between yourselves, possibly with the help of a mediator. If agreement can be reached it can be drafted by the solicitor into a separation agreement which is legally binding once registered through the courts.
Once there are no outstanding financial matters one of you can apply for divorce using the Simplified Procedure after one year's non-cohabitation with consent or two year non-cohabitation without consent if there are no children under 16 years of age. When there are children under 16 most people will require a solicitor to draft a writ to apply for divorce under the Ordinary Procedure.
Costs can be kept down by using solicitors efficiently producing documents in a timely manner, keeping to the point, dealing with several issues at the same time rather consulting about each problem as it arises and not using the solicitor as a counsellor.
Be very careful about using the internet and information that isn't specifically about divorce in Scotland. The legal system here is very different from that in England&Wales.