Gas chains Circle K and Sheetz are both slashing prices, effective today, on gas, reducing the price per gallon by 40 cents as people prepare for a busy Thanksgiving travel season.

Circle K’s offering is a short window, but it’s available on a much wider basis. On Nov. 21, the chain will offer 40 cents off each gallon pumped from 4 p.m. to 7 p.m. local time. Over 5,000 locations (including Holiday Superstores) will honor the promotion.

You can find the location closest to you at circlek.com/fuelday.

Sheetz is a smaller chain—and is only offering the 40-cent discount on a certain type of gas—its Unleaded 88—but is offering the deal for a considerably longer period. Drivers will be able to fill up at a discounted rate through the end of the month at 505 locations around the country that sell that brand of gas. (Find the one closest to you—or along your route—at the Sheetz website.

There are some restrictions: Certain states have regulations in place about gas discounts. Customers in Wisconsin, for example, who visit Circle K will be able to save only up to $4.50 with a minimum three-gallon purchase.

This is the second year in a row Sheetz has lowered the price of Unleaded 88, its hybrid gas, made of 15% ethanol and 85% gasoline, which is said to burn cleaner and have a higher octane level than pure gas. Last year, the chain dropped the price to $1.99 per gallon.

The Environmental Protection Agency says Unleaded 88 can be used in cars made after 2001, light-duty trucks, and medium-duty SUVs. (Some people, however, report they get lower gas mileage using the flex fuel.)