This seems a rather silly question but standard UK postage applies and it is up the the sender wheter they use first or second class. Postage costs for different letter sizes are available at the Royal Mail web site.
From Glasgow to Brentwood in Essex is about 400 miles. It would take between 6½ to 7 hours by car, or 6 hours by train.
That will depend on the value of the stamps you have. If you have one cent stamps you will need 190 of them. If you have ten cent stamps you only need 19.
Yes you need a valid passport to fly from Glasgow to Spain.
Essex is a whole county. There would be at least one hour's drive from one end of Essex to the other, so you would need to specify the town in Essex.
you need ten stamps actually i don't know
what the price to mail letter to
3 stamps!
you need to use 30 litres of petrol if you are going from Aberdeen to Glasgow
4 stamps
it depends on the stamp then you will know how many stamps you will need
i believe you do.
maybe 2 0r 3 stamps