Where do you buy Tygon from locally or online?
Online or by phone, McMaster-Carr. You can check out there online catalog. They do have a very big paper catalog, but you have to be a fairly big regular customer before they will give you one, and they do not sell them. Sometimes you can find a McMaster-Carr catalog for sale on e-bay. Usually the ones you find on e-bay are older versions. The most recent version ones will go for a significantly higher price. Only huge customers of McMaster-Carr get more than one catalog and then sell some of the recent ones. When McMaster-Carr sends out new versions of the catalog the older versions go on sale on e-bay. You really do not need to get a paper catalog, everything they sell is on their web-site, but the paper catalog is organized into sections and sometimes that makes finding stuff easier if you have one. There is nothing wrong with buying one of their catalogs that is only one version older than the most recent, and those ones cost much less.
McMaster-Carr is one of the biggest customers of UPS, and as as such they have a very special arrangement with UPS. They get super cheap rates that they pass on to their customers, and along with the very low rates they get super fast service. Place the order before noon eastern standard time, and you can expect the item to appear at your location the next day more than 90 % of the time. They are very fast about filling orders, and the low cost fast service of UPS is almost unbelievable.
The variety of products that McMaster-Carr sells is huge. You can find just about anything related to any kind of hardware and many other items on their site. Need a special bearing, they probably have it, need a special bolt, or drill bit, or tool they probably have it.
BTW, there are different types of Tygon tubing. If you read the McMaster-Carr catalog they will tell you which one is suitable for use with gasoline. Be sure the type you get is rated for gasoline.