# Invoice Simple vs FLEX PLUS

The clearest difference is rating: Invoice Simple at 4.9 against FLEX PLUS's 1.0. Invoice Simple also leads on update cadence (every 2 weeks vs every 46 months) and ratings volume (123K vs 1). FLEX PLUS's advantage is in-app purchases (none vs 10) and iOS requirement (10.0 vs 16.4). On price, ads and device support there is nothing between them.

Both are free to download. Invoice Simple sells 9 in-app purchases, starting at $6.99 per month. FLEX PLUS asks for nothing beyond the download.

Invoice Simple holds the better App Store score, 4.9 against 1.0. That said, the two scores are not equally well evidenced: Invoice Simple has 123K ratings behind it against 1, so its average is the more settled of the two.

Invoice Simple ships an update every 2 weeks, FLEX PLUS every 46 months. The most recent releases landed on November 4, 2026 and November 3, 2026 respectively.

## The numbers

| Metric | Invoice Simple | FLEX PLUS |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.9 (123K ratings)](https://appshunter.io/ios/app/invoice-simple-invoice-maker/id694831622/reviews)** | [1.0 (1 ratings)](https://appshunter.io/ios/app/flex-plus/id1492429745/reviews) |
| Number of ratings | **123K** | 1 |
| Positive reviews | 63.8% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | **Every 2 weeks** | Every 46 months |
| Monetization | Free with in-app purchases | **Free** |
| Best chart rank | **#9** | — |
| Size | 221 MB | 11 MB |
| Requires iOS | 16.4 | **10.0** |
| Devices | iPhone, iPad | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Zenvoice Inc.](https://appshunter.io/developer/990870994) | [FLEX-ING HOLDINGS LIMITED](https://appshunter.io/developer/1492341311) |

## What reviewers say

### Invoice Simple

[App page](https://appshunter.io/ios/app/invoice-simple-invoice-maker/id694831622)

**Currently charting:** #9 Top Grossing · Business (US App Store)

Create and send professional invoices, estimates, and receipts quickly from your mobile device. This app helps individuals and growing businesses get organized, look professional, and get paid faster by accepting online payments.

**Highlights:** Create invoices, estimates, and receipts, Accept online payments, Customize invoices with logo and details, Organize client and product information, Send via email, text, or WhatsApp, Download as PDF, Get payment and opening alerts

**Features:** iPhone Duo support

**In-app purchases (9)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Essentials Monthly | $6.99 | per month |
| Mobile subscription | $10.99 | per month |
| Monthly Side Business | $10.99 | per month |
| Monthly Business Sub | $11.99 | per month |
| Monthly Subscription | $11.99 | per month |
| Monthly subscription | $13.49 | per month |
| Plus Monthly | $14.99 | per month |
| Monthly Standard Subscription | $17.99 | per month |
| Premium Monthly | $21.99 | per month |

**What reviewers like**

- 🚀 Easy to use
- 👍 Professional-looking invoices
- 🚀 Quick and simple
- 👍 Saves time
- 👍 Convenient mobile access

**What reviewers complain about**

- 💰 Expensive subscription
- 🐛 Glitches and bugs
- 🔀 Inconsistent features across platforms
- 🔀 Confusing navigation
- 🔀 Limited customization options

**Reported bugs**

- Invoices not sending properly
- App crashing or freezing
- Inability to recover deleted invoices
- Syncing issues between mobile and desktop

**Requested features**

- Add ability to rearrange line items
- Improve search and filtering capabilities
- Integrate with accounting software
- Add option to track expenses and profitability
- Allow multiple business profiles in one account


### FLEX PLUS

[App page](https://appshunter.io/ios/app/flex-plus/id1492429745)

This platform provides a convenient way to order from local stores and receive deliveries at your preferred location. It offers a user-friendly interface, loyalty points for discounts, and real-time order tracking. Explore a wide range of categories and enjoy personalized recommendations.

**Highlights:** Order from favorite stores, Delivery to preferred location, User-friendly registration, Promotions and loyalty points, Real-time order tracking, Wide range of product categories

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Invoice Simple free?

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

### Is FLEX PLUS free?

FLEX PLUS is free to download, with no in-app purchases.

### Which has better reviews, Invoice Simple or FLEX PLUS?

Invoice Simple is rated higher. Invoice Simple averages 4.9 out of 5 from 123K ratings, while FLEX PLUS averages 1.0 from 1 ratings.

### Do Invoice Simple or FLEX PLUS have ads?

Neither Invoice Simple nor FLEX PLUS shows ads.

### Which is updated more often, Invoice Simple or FLEX PLUS?

Invoice Simple ships an update every 2 weeks, and FLEX PLUS every 46 months. Most recently, Invoice Simple was updated on November 4, 2026 and FLEX PLUS on November 3, 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.*