Low-cost retail CO2 bottles?

A bit OT, but would any of the amateur laser makers on this group know
the best (cheapest) way to purchase retail CO2 bottles, with slow-flow
regulators, for home use?

(Not for CO2 lasers, actually -- one of the ways to fight an infestation
of moles and ground squirrels in a lawn is allegedly to direct a slow
flow of CO2 into the tunnel system. So, what's the easiest way to
purchase low-cost, low-purity, low-hassle CO2 in small amounts?
Already tried dry ice -- works, but expensive, and can't store it for
long periods. Fire extinguisher refills also seem to be expensive.)
.

Relevant Pages

  • Re: Low-cost retail CO2 bottles?
    ... but would any of the amateur laser makers on this group know ... >the best way to purchase retail CO2 bottles, with slow-flow ... >regulators, for home use? ... >(Not for CO2 lasers, actually -- one of the ways to fight an infestation ...
    (sci.optics)
  • Re: Low-cost retail CO2 bottles?
    ... the best way to purchase retail CO2 bottles, with slow-flow regulators, for home use? ... of moles and ground squirrels in a lawn is allegedly to direct a slow flow of CO2 into the tunnel system. ... David Littlewood ...
    (sci.optics)