What is the best alternative to mobile-pocket loyalty cards on iPhone?

WinStamp - Loyalty Card, S tier, #2 in loyalty card wallet.

Is there a free alternative to mobile-pocket loyalty cards?

Yes: WinStamp - Loyalty Card (S tier, #2) is free, with no in-app purchases.

No. mobile-pocket loyalty cards is #1 in loyalty card wallet.

mobile-pocket loyalty cards is S tier, #1 of 7 in loyalty card wallet. Here is everything that competes with it on iPhone, in tier order.

2
WinStamp - Loyalty CardS
Free · ★ 4.9 · 4,020 ratings · score 93
Stores loyalty card stamps from participating businesses in one app, using a personal QR code shown at checkout.
3
Stamp MeS
Free · ★ 5.0 · 2,480 ratings · score 91
Digital loyalty card app that stores stamp cards from participating businesses and tracks rewards on your phone.
4
Card Manager: Digital WalletA
Free + IAP · ★ 4.7 · 2,016 ratings · score 86
Stores gift, loyalty, membership and other cards in one app, with Apple Wallet support and offline use.
5
Pass2U Wallet - Add store cardA
Free + IAP · ★ 4.2 · 2,896 ratings · score 83
Stores store cards, coupons, event tickets and boarding passes as digital passes in Apple Wallet, created by scanning.
6
Key Ring Rewards Card WalletB
Free · ★ 4.6 · 20,118 ratings · score 79
Stores loyalty, membership, and library cards digitally and lets you build and share shopping lists.
7
BJs Wholesale ClubB
Free · ★ 4.8 · 1,080,084 ratings · score 74
BJ's Wholesale Club app for members: coupons, gas prices, club details, pickup, delivery and membership access.

What is the best alternative to mobile-pocket loyalty cards on iPhone?: WinStamp - Loyalty Card, S tier, #2 in loyalty card wallet.
Is there a free alternative to mobile-pocket loyalty cards?: Yes: WinStamp - Loyalty Card (S tier, #2) is free, with no in-app purchases.
Does anything rank above mobile-pocket loyalty cards?: No. mobile-pocket loyalty cards is #1 in loyalty card wallet.