Cheapest Gas in Thornton, CO

Updated May 20, 2026 — Prices updated regularly from EIA data

$2.87

Lowest price at Costco in Thornton

Finding Cheap Gas in Thornton

Hunting down the lowest gas price in Thornton, Colorado is worth the effort. At $$2.87 per gallon at the cheapest outlet versus $$3.12 at the most expensive, you save $$3.75 on every 15-gallon fill-up.

Maximum Savings in Thornton

Choose Costco over Chevron

$0.25 per gallon

$3.75 per 15-gallon fill • $12.00 per year (est.)

Cheapest Brands in Thornton

Rank	Brand	Est. Price	Savings vs. Most Expensive
#1	Costco	$2.87	$0.25
#2	Speedway	$2.99	$0.13
#3	Circle K	$3.00	$0.12
#4	Sunoco	$3.03	$0.09
#5	Marathon	$3.04	$0.08
#6	BP	$3.06	$0.06
#7	Mobil	$3.07	$0.05
#8	Exxon	$3.08	$0.04
#9	Shell	$3.10	$0.02
#10	Chevron	$3.12	$0.00

Gas Saving Tips for Thornton Drivers

Sign up for gas station loyalty apps — Shell Fuel Rewards, Marathon MakeItCount, and Circle K Inner Circle all offer genuine per-gallon discounts that compound over time.
Use a gas rewards credit card. The Costco Citi Visa earns 4% back on eligible gas; Blue Cash Preferred earns 3% at US gas stations. Pairing a reward card with a warehouse club maximizes savings.
Avoid filling up at highway exits, airports, and tourist areas where convenience premiums routinely add 15-25 cents per gallon.
Keep your tires properly inflated to the manufacturer's recommended PSI — under-inflated tires reduce fuel economy by up to 3%, costing you money every mile.
Accelerate and brake gradually. Aggressive driving can reduce fuel economy by 15-40%, directly increasing how often you fill up.