Christian Missions in Persia. Christianity was introduced in Persia in the Parthian period, and several bishoprics were established there (Latourette, II, pp. 263ff.).
You will likely pay more for the exchange, even if your tank is completely empty. An empty 20 lb tank will hold about 4.7 gallons of propane. That is $18.47 at $3.93 per gallon, which is the low quantity price (I just paid $3.44 per gallon when filling several tanks). The exchange is about the same price. Keep in mind this comparison is as if the exchange gives you a FULL tank.
1 Installing an underground tank can cost around $1,800-$3,000 for 500 gallons and $2,000-$3,500 or more for 1,000 gallons. 2  A Wisconsin propane dealer charges $1,599 to install a typical 500-gallon aboveground tank and $2,995 for a 1,000-gallon underground tank. Buying and installing a customer-owned aboveground propane tank runs about $450-$1,000 for a 120- or 250-gallon tank and $800-$2,500 for a 500-gallon aboveground tank.