San Marcos Average Gas Price
| Regular | Mid-Grade | Premium | Diesel | E85 | |
|---|---|---|---|---|---|
| Week Ago Avg. | $2.9 | $3.2 | $3.72 | $3.4 | $2.66 |
| Month Ago Avg. | $2.79 | $3.16 | $3.61 | $3.28 | $2.66 |
Highest Recorded Average Gas Price In San Marcos Year to Date
| Price | Date | |
|---|---|---|
| Diesel | $3.4 | 03/22/26 |
| Regular | $2.9 | 03/18/26 |
Top 10 Gas Stations & Cheap Fuel Prices in San Marcos
Murphy Express in San Marcos (1201 SH-80)
1201 SH-80, San Marcos, Texas,
$2.92
Mar 31, 2026
0¢ Cashback
Exxon in San Marcos (2041 IH-35 N Ste 104)
2041 IH-35 N Ste 104, San Marcos, Texas,
$2.99
Mar 31, 2026
0¢ Cashback
Texaco in San Marcos (15610 Texas Hwy 123)
15610 Texas Hwy 123, San Marcos, Texas,
$3.00
Mar 31, 2026
0¢ Cashback
H-E-B in San Marcos (641 E Hopkins St)
641 E Hopkins St, San Marcos, Texas,
$3.07
Mar 31, 2026
0¢ Cashback
Shell in San Marcos (207 I 35 Frontage Rd)
207 N IH-35, San Marcos, Texas,
$3.14
Mar 31, 2026
3¢ Cashback
Valero in San Marcos (420 Sarah St)
420 Sarah St, San Marcos, Texas,
$3.19
Mar 31, 2026
0¢ Cashback
Sunoco in San Marcos (3936 IH-35 S)
3936 IH-35 S, San Marcos, Texas,
$3.19
Mar 31, 2026
0¢ Cashback
Chevron in San Marcos (115 Wonderworld Dr)
115 Wonderworld Dr, San Marcos, Texas,
$3.39
Mar 31, 2026
0¢ Cashback
Shell in San Marcos (5403 IH-35 S)
5403 IH-35 S, San Marcos, Texas,
$3.69
Mar 31, 2026
3¢ Cashback
Shell in San Marcos (207 I 35 Frontage Rd)
207 North Interstate 35, San Marcos, Texas,
$3.96
Mar 31, 2026
3¢ 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.