What is the best alternative to Splitwise on iPhone?

tricount: Split & Settle Bills, S tier, #1 in bill splitting.

Is there a free alternative to Splitwise?

Yes: tricount: Split & Settle Bills (S tier, #1) is free to download.

Yes. 2 apps rank above it in bill splitting: tricount: Split & Settle Bills (#1), Splid - Split group bills (#2).

Splitwise is S tier, #3 of 6 in bill splitting. Here is everything that competes with it on iPhone, in tier order.

1
tricount: Split & Settle BillsS
Free download · ★ 4.9 · 7,432 ratings · score 96
Free app to split group expenses, track shared bills, and settle balances with friends, roommates, or partners.
2
Splid - Split group billsS
Free download · ★ 4.9 · 4,158 ratings · score 91
Splits group expenses and shows who owes whom, with offline groups, multiple currencies and PDF or Excel summaries.
4
Tip Calculator % GoldB
Free + IAP · ★ 4.8 · 61,179 ratings · score 71
Free tip calculator for entering bills quickly, splitting them among diners, and rounding tips to an exact amount.
5
iTip Calc by PalaSoftwareC
Free download · ★ 4.8 · 9,969 ratings · score 69
Calculates tip, grand total, and per-person share for a bill, with optional receipt scanning and PDF summaries.
6
Tip Calculator Plus+D
Free download · ★ 4.8 · 6,917 ratings · score 59
Calculates tips and splits bills among friends, with quick data entry and total value rounding.

What is the best alternative to Splitwise on iPhone?: tricount: Split & Settle Bills, S tier, #1 in bill splitting.
Is there a free alternative to Splitwise?: Yes: tricount: Split & Settle Bills (S tier, #1) is free to download.
Does anything rank above Splitwise?: Yes. 2 apps rank above it in bill splitting: tricount: Split & Settle Bills (#1), Splid - Split group bills (#2).