A buddy and I sell it and charge around $40 to fill a 10# bottle. But, when we buy a mother bottle it only takes selling about four 10 lbs. bottles to pay for the mother bottle and we get between 3-4 fills free. I usually pay about 10 bucks that I throw in the "pot" to keep a good supply of funds in the spray account...

 

I know it is not your area however I found a place in the Poconos (PA) that sells N2O for $8 a pound. Consider your $5 places in TX a blessing!