Both are FCA regulated and FSCS protected. The real differences are fees, investment range and how each platform feels to use. Here is the honest comparison.
Fees verified July 2026. Capital at risk. Information, not financial advice.
Index fund investors who want the lowest possible total cost and are comfortable with a newer app.
Beginners building a habit, and first-time buyers using the Lifetime ISA.
| Fee | Prosper | Moneybox |
|---|---|---|
| Platform fee | £0 | £1/month subscription plus 0.45% platform fee |
| Share dealing | Not applicable (funds and ETFs) | US stocks available, 0.45% FX fee |
| Fund dealing | Free | Free (fund fees apply) |
| FX fee | None on GBP fund classes | 0.45% on US stocks |
| Stocks & Shares ISA | Free | Subscription plus 0.45% applies |
| SIPP | Free | 0.45% platform fee (0.15% above £100k), no subscription |
| Withdrawals | Free | Free |
| Minimum to start | No minimum | £1 |
Early adopters praise the zero fees and responsive founding team; roughly 84% of reviews are five stars.
The review base is small and some users want more account types and a web version.
Read Prosper reviews on TrustpilotUsers love the round-ups, the goal-based design and how painless it makes starting. 93% of customers surveyed in 2026 would recommend it.
The combined £1/month plus 0.45% is repeatedly flagged as expensive for small balances.
Read Moneybox reviews on TrustpilotProsper's pitch is the cheapest total cost of ownership in the UK: no platform fee, no dealing fees, and refunded fund fees on a list of mainstream index funds. For a straightforward global tracker in an ISA or SIPP, the all-in cost can genuinely be zero.
The counterweight is maturity. It is a young platform with a small (if very positive) review base and no individual shares. If that trade-off suits you, the price is unbeatable.
Moneybox is designed for getting started. Round-ups, weekly deposits and simple starter portfolios remove the friction that stops most people investing, and its Lifetime ISA is one of the most popular routes to a first home deposit.
The convenience has a price: £1 a month plus 0.45% is one of the higher fee stacks here once your balance grows. It is a great first platform, and many users graduate to cheaper ones later.
A 0.2% fee difference is worth optimising. Knowing whether you are saving enough in the first place is worth far more. Delphina models your pensions, ISAs and investments and tells you where you actually stand.