Spider Morph is my first morph too. I only got mine on the 17th of July, and I'm still learning!

I paid £65 for mine- Without the setup (viv= £50, decor, around £28 and heating etc £40) So I paid about 180 for mine//
£120 is a good deal in my opinion. If you have the money, and you want the snake- go for it

And as albinos_rule said, the spider morph has a slight genetic defect. Their heads have a slight wobble when they are trying to keep still, and sometimes they corkscrew (when the head decides to go up-side down) Its just due to the inbreeding and crossbreeding done to get the desired morph. Its servarity varies with the individual, but if the guy who is selling it says he isnt that affected, that's brilliant. My boy has it, but it doesn't affect him at all. it is a little amusing too when he decides to go one way, and he suddenly turns upside down lol

I hope it goes well with you both. I look forward to hearing the updates