# IOU vs Source Note

The clearest difference is ads: Source Note at none against IOU's shown. Source Note also leads on iOS requirement (15.0 vs 18.4). IOU's advantage is update cadence (every 4 days vs every 2 weeks). On price, in-app purchases and device support there is nothing between them.

Both are free to download. IOU sells 1 in-app purchase, starting at $9.99 per month and Source Note sells 2 in-app purchases, starting at $5.99 per 7 days. Whichever you choose, the download price is not the number that matters.

IOU ships an update every 4 days, Source Note every 2 weeks. The most recent releases landed on September 28, 2026 and September 24, 2026 respectively.

## The numbers

| Metric | IOU | Source Note |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (8 ratings)](https://appshunter.io/ios/app/iou-marker/id6746040680/reviews)** | — |
| Number of ratings | **8** | — |
| Positive reviews | 83.3% of reviews | — |
| In-app purchases | Yes | Yes |
| Ads | Yes | **No** |
| Update frequency | **Every 4 days** | Every 2 weeks |
| Monetization | Ad-supported | — |
| Size | 148 MB | 45 MB |
| Requires iOS | 18.4 | **15.0** |
| Devices | iPhone | **iPhone, iPod** |
| Age rating | 17+ | 4+ |
| Developer | [IOU Marker](https://appshunter.io/developer/1814814238) | [TOPMUSE PTE. LTD.](https://appshunter.io/developer/1753894501) |

## What reviewers say

### IOU

[App page](https://appshunter.io/ios/app/iou-marker/id6746040680)

Create professional agreements and manage payments effortlessly. Draft documents using AI, e-sign, and track invoices and due dates in one organized platform. Secure sign-in ensures your data is protected.

**Highlights:** AI-powered agreement drafting, E-signature functionality, Payment and invoice management, Due date reminders, Dispute tracking, Secure sign-in

**Features:** macOS Compatibility, Apple Wallet, Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| IOU Pro | $9.99 | per month |


### Source Note

[App page](https://appshunter.io/ios/app/source-note-procurement-log/id6760685975)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Source Note,1week | $5.99 | per 7 days |
| Source Note,1year | $59.99 | per year |


## Frequently asked questions

### Is IOU free?

IOU is free to download, with in-app purchases available.

### Is Source Note free?

Source Note is free to download, with in-app purchases available.

### Do IOU or Source Note have ads?

IOU shows ads; Source Note does not.

### Which is updated more often, IOU or Source Note?

IOU ships an update every 4 days, and Source Note every 2 weeks. Most recently, IOU was updated on September 28, 2026 and Source Note on September 24, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*