Nerf Battle Racer Go Kart was £279.99, now £159.99. You may be able to make it even cheaper with discount codes. I have code LMVQU for 15% off, but I haven't tried to use it on this as there are exclusions. I believe this is a good price for this. I paid around £200 at Christmas last year with a discount codes.
There are other different cheaper go karts out there and also very has a sale on a few such as this one Batman Hurricane - Go Kart @ £109.99, but my son absolutely loves this one with his nerf guns and all the kids at the park ask to play on it too. I bought this for my 7 year old son last Christmas.
It is easy to put together, but it does come in a quite heavy massive box.
Details copied from site:
Unleash your Nerf weapons on the move with this awesome Battle Racer.
It can carry up to four Nerf blasters and a big supply of Nerf darts so you can take your Nerf fun with you anywhere.
It has a rugged steel frame, forward/reverse gears plus free-wheel function and a hand brake.
It also features a tool-free adjuatable seat and easy chain tensioning to keep it running nice and smooth too.
Depth: 125 CM
Height: 69 CM
Width: 59.5 CM
Age Range: 4+
Assembly: Part Assembled
Experience Level: Beginner
Warning Message: Warning: Not suitable for children under 3 years
Carries up to 4 Nerf Blasters
Holders for loads of Nerf darts
Sturdy steel frame
tool-free adjustable seat
Forward and reverse gears
Easy chain driive adjustment
From age 4 to 10 years