Clark Gas Stations peaked in the 1970's owning and running about 1500 service stations throughout the United States. Since then some downsizing and asset sales have taken place but the latest numbers show there are still around 700 branded gas stations operating throughout the United States many of which have convenience stores attached operating under the name "On the Go". Like most gas stations the company listed (Clark) normally only provides the petroleum, diesel and branding while the gas station itself is privately owned. This means that some Clark stations sell stamps while others do not. It is entirely up to the owner of the store. I sent Clark's head office an email to see if they could provide any additional information.
Good morning, Ashley,
Thank you for your email. As each store is independently owned and operated, you would need to call the Clark Store nearest you and ask if they carry stamps; we at corporate do not know the products carried in each store.
They did not have any info on how many of their stores sold postage stamps so I guess it just comes down to luck of the draw. It's easy to look up the phone number of your closest Clark gas station if you want to ask them if they have any in stock. To make it even easier I have made a map below which can be used to find the details of any Clark gas station in your area. Just enter your towns name below and hit enter.
Okay great. You have found a service station that sells postage stamps. Now what should you be buying?
Most likely any stamps bought from a Clark service station will be
USA Forever stamps. These stamps can be used on any letter or package (provided you put enough on for the weight). And as a bonus they increase in value if the price of standard mail is increased (you will notice they don't have a denomination listed on them). They are valid forever which means if you don't use them all at once you can chuck them in the draw and use them again next time you need to send a letter.
Okay you've found some stamps and attached them to your letter. Now what do you do? Over the last few years one of the USPS priorities was to make drop boxes as convenient as possible for people throughout the US. One of the ways they have done this is by adding drop boxes to a number of large gas stations and truck stops throughout the country. If you see a brightly colored box inside or outside the gas station then you are in luck. Another option you have is to ask the person at the checkout if you can give them your letter and they add it to their outgoing mail pile. This is up to the decision of the person working buy I have done it a few times over the years and never had an issue (just don't have anything too important in the letter).