# Stack Trainer vs Buddy for KAIST

The clearest difference is price: Buddy for KAIST at Free against Stack Trainer's $3.99. Buddy for KAIST also leads on in-app purchases (none vs 2) and update cadence (every 3 weeks vs every 3 months). Stack Trainer's advantage is iOS requirement (15.6 vs 26.1). On ads and device support there is nothing between them.

Buddy for KAIST is free to download; Stack Trainer costs $3.99 up front. Stack Trainer sells 2 in-app purchases, starting at $1.99 per 3 months. Buddy for KAIST asks for nothing beyond the download.

Stack Trainer ships an update every 3 months, Buddy for KAIST every 3 weeks. The most recent releases landed on October 7, 2026 and October 24, 2026 respectively.

## The numbers

| Metric | Stack Trainer | Buddy for KAIST |
| --- | --- | --- |
| Price | $3.99 | **Free** |
| Rating | **[1.0 (1 ratings)](https://appshunter.io/ios/app/stack-trainer/id646458442/reviews)** | — |
| Number of ratings | **1** | — |
| Positive reviews | 0.0% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 3 months | **Every 3 weeks** |
| Monetization | Subscription | — |
| Size | 6 MB | 61 MB |
| Requires iOS | **15.6** | 26.1 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, Apple Watch |
| Age rating | 4+ | 4+ |
| Developer | [Ralph Cos](https://appshunter.io/developer/573505028) | [SPARCS](https://appshunter.io/developer/1687472027) |

## What reviewers say

### Stack Trainer

[App page](https://appshunter.io/ios/app/stack-trainer/id646458442)

This app provides a realistic card deck experience for close-up magicians to train their memory of card stacks. It offers various challenge modes and filters to aid learning and practice, with a focus on a clean, distraction-free interface.

**Highlights:** Realistic card deck simulation, Multiple mnemonic training approaches, Customizable stack filters, Lorrayne's peg words integration, Interactive quick-touch analyzer, Display and whisper modes

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| 3 Months Subscription | $1.99 | per 3 months |
| Annual Subscription | $2.99 | per year |


### Buddy for KAIST

[App page](https://appshunter.io/ios/app/buddy-for-kaist/id6749929416)

**Features:** macOS Compatibility, Apple Watch app, Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is Stack Trainer free?

Stack Trainer costs $3.99, and also offers in-app purchases.

### Is Buddy for KAIST free?

Buddy for KAIST is free to download, with no in-app purchases.

### Do Stack Trainer or Buddy for KAIST have ads?

Neither Stack Trainer nor Buddy for KAIST shows ads.

### Which is updated more often, Stack Trainer or Buddy for KAIST?

Stack Trainer ships an update every 3 months, and Buddy for KAIST every 3 weeks. Most recently, Stack Trainer was updated on October 7, 2026 and Buddy for KAIST on October 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.*