First of all, you need to understand what size the bottles come in:

Welding Cylinder Data

OXYGEN
Capacity Height Diameter
K 251 51" 9"
S 156 46" 7-3/8"
M 125 47" 7"
Q 92 30" 7-1/8"

ACETYLENE
#5 350 45" 12"
#4 150 38" 8"
#3 75 29" 7"

I believe that all of these sizes are used in home shops.

Now, to answer your question. In my area the prices for welding gasses vary
buy over 50% within a 20 mile radius, so if your money is worth more than your
time, it pays to shop around and drive for it. The last time I refilled I did
it at the close place, NOT the cheap place, and I paid:

(oxygen) M size: $23.73 ;; (acetylene) #3 size: $38.91

Grant Erwin
Kirkland, Washington

To The Group wrote:
Just a curious question for the group.

Using the standard size bottles for acetylene and oxygen found in most
shops and garages what does a refil cost.