Cheapest Gas in Rapid City, SD
Updated April 5, 2026 — Prices updated regularly from EIA data
$2.95
Lowest price at Costco in Rapid City
Finding Cheap Gas in Rapid City
Gas prices in Rapid City, South Dakota vary significantly by brand and location. This guide identifies today's most affordable options — potentially saving the average driver $$12.00 or more annually.
Maximum Savings in Rapid City
Choose Costco over Chevron
$0.25 per gallon
$3.75 per 15-gallon fill • $12.00 per year (est.)
Cheapest Brands in Rapid City
| Rank | Brand | Est. Price | Savings vs. Most Expensive |
|---|---|---|---|
| #1 | Costco | $2.95 | $0.25 |
| #2 | Speedway | $3.07 | $0.13 |
| #3 | Circle K | $3.08 | $0.12 |
| #4 | Sunoco | $3.11 | $0.09 |
| #5 | Marathon | $3.12 | $0.08 |
| #6 | BP | $3.14 | $0.06 |
| #7 | Mobil | $3.15 | $0.05 |
| #8 | Exxon | $3.16 | $0.04 |
| #9 | Shell | $3.18 | $0.02 |
| #10 | Chevron | $3.20 | $0.00 |
Gas Saving Tips for Rapid City Drivers
- Check if your grocery store offers fuel rewards. Kroger, Safeway, Giant, and many regional chains discount gas by 10-50 cents per gallon tied to grocery spending thresholds.
- Use regular unleaded unless your owner's manual specifically requires premium. For the majority of vehicles, there is zero performance benefit from a higher grade.
- Plan fill-ups along your existing commute route rather than making special trips. A station you pass daily that is 10 cents cheaper beats a special detour to a slightly better price.
- Pay cash at stations offering a cash vs. credit discount — typically 5-10 cents per gallon savings that adds up significantly over time.
- Do not let your tank run below a quarter — low fuel levels increase wear on electric fuel pumps and can lead to emergency fill-ups at inconvenient and expensive stations.
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