(07 May 2015, 8:04 pm)Malarkey wrote The Edinburgh one looks rather tempting for £17.50 mind.
That's decent for Edinburgh. It's worth keeping an eye on the rail fares though, as you can do Edinburgh and back on fixed tickets for not a lot.
I'd also recommend checking fares for Newcastle to Glasgow Queen Street/Central, because the stretch between Glasgow and Edinburgh is open ticket, despite being fixed between Newcastle and Edinburgh.