Basically, as follows..
An A3 (420mmx297mm) drawing, with one subject ( eg, one car ), framed, packaged well and delivered to your door, will cost just £250.
Futher subjects within the same drawing, are £50 per subject.
As above, but A2 in size, will start at £300 and £60 per extra subject.
For an even larger A1 drawing, £350 and £70 per extra subject.
So, not as much as you'd think, for personalised fine art!