San Marcos Average Gas Price
| Regular | Mid-Grade | Premium | Diesel | E85 | |
|---|---|---|---|---|---|
| Week Ago Avg. | $3.24 | $3.42 | $3.88 | $3.91 | $2.85 |
| Month Ago Avg. | $3.23 | $3.42 | $3.87 | $3.85 | $2.85 |
Highest Recorded Average Gas Price In San Marcos Year to Date
| Price | Date | |
|---|---|---|
| Diesel | $3.91 | 07/12/26 |
| Regular | $3.24 | 06/17/26 |
Top 10 Gas Stations & Cheap Fuel Prices in San Marcos
Texaco in San Marcos (15610 Texas Hwy 123)
15610 Texas Hwy 123, San Marcos, Texas,
$3.00
Jul 19, 2026
0¢ Cashback
Murphy Express in San Marcos (1201 SH-80)
1201 SH-80, San Marcos, Texas,
$3.59
Jul 19, 2026
0¢ Cashback
Exxon in San Marcos (1103 SH-80)
1103 SH-80, San Marcos, Texas,
$3.59
Jul 19, 2026
0¢ Cashback
Sunoco in San Marcos (1903 N IH-35)
1903 N IH-35, San Marcos, Texas,
$3.64
Jul 19, 2026
0¢ Cashback
Valero in San Marcos (1550 IH-35 N)
1550 IH-35 N, San Marcos, Texas,
$3.64
Jul 19, 2026
0¢ Cashback
Mill Street Market Fuel in San Marcos (641 Mill St)
641 Mill St, San Marcos, Texas,
$3.79
Jul 19, 2026
0¢ Cashback
Valero in San Marcos (1002 SH-80)
1002 SH-80, San Marcos, Texas,
$3.79
Jul 19, 2026
0¢ Cashback
Texaco in San Marcos (1501 Post Rd)
1501 Post Rd, San Marcos, Texas,
$3.79
Jul 19, 2026
0¢ Cashback
Exxon in San Marcos (339 N Guadalupe St)
339 N Guadalupe St, San Marcos, Texas,
$3.89
Jul 19, 2026
0¢ Cashback
Exxon in San Marcos (1636 Aquarena Springs Dr)
1636 Aquarena Springs Dr, San Marcos, Texas,
$3.94
Jul 19, 2026
0¢ Cashback
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Gas Data Methodology
The fuel prices published in this guide are based on the results of research completed by Way.com’s data team. Using a mix of external and internal data, we analyzed millions of prices across U.S. ZIP codes and globally.