Of course I am not stopping you, but sometimes the cheaper shed may not last for many more Easters, so best to spend that little bit more and go for Pressure Treated wood.
The main online providers are very competitive at the moment but I doubt you will get your shed in time for the break to be able to start pottering around in it..
If I was buying then, these ones have caught my eye as they are good for what you get, as sometimes if you don’t have the time/effort/skills
7’1×6’10 (2.16×2.07m) Larchlap Pressure Treated Overlap 77PT From ShedStore.
Heavy Duty Shed 8′ x 6′ From taylors
BillyOh Greenkeeper Premium Apex From Garden buildings Direct
Of course the big DIY retailers are also trying to get your Easter Cash as well
Apex Shiplap Pressure Treated Shed – Model 137 – (H) 7ft x (W) 6ft5in x (D) 13ft3in From B&Q
Heavy Duty Shed 8×6 from Focus DIY
Of course why not buy from the Shed Shops, here & here !! and I might be able to afford that wooden castle that the shedmaster deserves