Here are several affordable, well-reviewed power-bank options that work well with Android phones, plus quick buying tips so you pick the right one for your needs.

Top affordable picks

• Baseus Airpow (10,000 mAh, ~20W): compact, inexpensive, and feature-packed for the price — solid everyday option if you want a low-cost, multi-port 10K pack. (techradar.com)
• Belkin BoostCharge 10K (10,000 mAh): one of the simplest, budget-friendly 10K packs (good build and value if you don’t need super-fast charging). (wired.com)
• Anker Nano / PowerCore (10,000 mAh, 30W variants): a step up if you want compact size plus faster USB‑C PD charging (good for quick top-ups on modern Android phones). (anker.com)
• UGREEN Nexode 12,000 mAh (100W-capable internals on some models): a good mid-range value if you want higher power and multi-device support without a big price jump. (tomsguide.com)
• Anker PowerCore / Speed 20,000 mAh (20–22.5W): affordable 20K options that give multiple full phone charges — better when you need more capacity for day trips. (techadvisor.com)
• Xiaomi Power Bank 20,000 mAh (integrated cable, very low price in some markets): excellent value where available, but availability and regional models vary — check US retailers before buying. (notebookcheck.net)

Quick buying tips (for Android)

• Capacity vs real-world: a 10,000 mAh pack typically gives ~1–2 full phone charges; 20,000 mAh gives ~2–4 depending on your phone and conversion losses. Manufacturers rate cells at 3.7V, so usable output is lower. (techradar.com)
• Look for USB‑C Power Delivery (PD) or Quick Charge support: PD at 18–30W is a good sweet spot for fast top-ups on most Android phones. If you want very fast charging or laptop support, look for higher-watt models but expect a higher price. (anker.com)
• Built-in cable vs ports: built-in USB‑C cables are convenient but limit flexibility; separate USB‑C ports let you charge multiple devices or use your preferred cable. (anker.com)
• Airline rules and safety: power banks must be carried in carry‑on (not checked) and most airlines limit spare Li‑ion batteries to 100 Wh (about 27,000 mAh at 3.7V) unless you have airline approval. Check TSA/airline rules before flying. (tsa.gov)
• Avoid very-cheap no-name units that lack safety certifications — reputable brands (Anker, Baseus, UGREEN, Belkin, Xiaomi, etc.) generally offer better quality control and warranties. Tech sites’ buyer guides are useful when comparing real-world performance. (techradar.com)

If you want, I can:

• Narrow this to models under a specific price (e.g., <$30 or <$50) and show current Amazon/Best Buy links and prices; or
• Recommend the best single purchase for a specific Android phone model (tell me your phone and budget).