Comparison

Once Upon a Galaxy vs Cost Exchange

Price, ratings, monetisation and update history for both games, side by side — with what reviewers say about each.

Head to head
About

Once Upon a Galaxy

Embark on a fantasy card battling adventure where you draft unique captains and their friends to complete quests. Choose your path with diverse characters and strategic gameplay. Experience a game free of ads and AI art, focusing on player choice and engaging battles.

Highlights
  • Fantasy card battling
  • Captain drafting
  • Quest completion
  • Strategic gameplay
  • No AI artwork
  • Asynchronous play
Features
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Galaxy is FREE to play, has NO ADS, uses NO AI artwork. Will you choose Dorothy as your captain and help her and friends on their journey to complete their quests? Or Dragonmother and discover what will hatch from her dragon egg? Or maybe Indiana Clones, who will "clone" your best three treasures? It's all up to you!

About

Cost Exchange

Features
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You are the duty officer on an air-defence console. Contacts appear on the scope. You do not know what they are. Query IFF, wait three seconds, then read the returned data — speed, altitude, radar cross section — and INFER the threat yourself. The game never labels it for you. Then the real decision: which weapon? An IR missile costs $150k. A radar missile costs $350k. CIWS costs $5k. The laser is free but needs time you may not have. Fire the expensive one at a cheap drone and you win the engagement while losing the operation. A leaker that reaches the centre damages a facility. Lose enough facilities and the operation is over — no matter how much money is left in the vault. • Infer, don't be told — no automatic threat labels, ever • Four weapons with real trade-offs in range, cost and reload • Ammunition economy: every shot is a decision you pay for • Graded S to F on five criteria, with hard caps for downing a friendly • DAILY OPERATION — the same operation for everyone, one attempt a day • FREE OPERATIONS — endless seeded operations across four difficulty tiers No ads. No energy timers. No in-app purchases. Everything is unlocked. iPhone and iPad.

Screenshots

Once Upon a Galaxy4 screens
Cost Exchange4 screens

Verdict

The call

The clearest difference is in-app purchases: Cost Exchange at none against Once Upon a Galaxy's 50. Once Upon a Galaxy's advantage is iOS requirement (15.0 vs 17.0). On price, ads and device support there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Once Upon a Galaxy sells 44 one-off in-app purchases. Cost Exchange asks for nothing beyond the download.

Scorecard2 real differences · 8 level
Once Upon a Galaxy versus Cost Exchange: the parameters behind the verdict, then further details
ParameterOnce Upon a GalaxyCost Exchange
PriceFreeFree
Rating4.8 (1.4K ratings) — better—
Positive reviews83.4% of reviews—
Number of ratings1.4K — better—
Update frequencyFortnightly—
AdsNoNo
In-app purchasesYesNo — better
MonetizationFree with in-app purchases—
DevicesiPhone, iPad, iPod — betteriPhone, iPad
Requires iOS15.0 — better17.0
Further details — not scored
Size195 MB3 MB
Age rating9+4+
DeveloperMillion Dreams GamesBurhanettin Uludag

Bugs and requests

Once Upon a Galaxy

Reported bugs

3 issues
  • Black screen on startup
  • Infinite loading issues
  • Progression loss after updates

Requested features

5 requests
  • More hero/card variety
  • Improved tutorial and learning tools
  • Offline/save progress mode
  • Cosmetic/non-gameplay monetization
  • Competitive/ranked modes

Cost Exchange

Not enough reviews yet to summarise bugs or requests.

In-app purchases

44 purchases

Once Upon a Galaxy

One-time44
  • 600 Gems (September deal)$4.99
  • 600 Gems (July deal)$4.99
  • Welcome Bundle3 variants$4.99
Show 41 more
  • 500 Gems2 variants$4.99
  • October 2026 Galaxy Pass$9.99
  • September 2026 Galaxy Pass$9.99
  • 1300 Gems (August deal)$9.99
  • August 2026 Galaxy Pass$9.99
  • July 2026 Galaxy Pass$9.99
  • June 2026 Galaxy Pass$9.99
  • March 2026 Galaxy Pass$9.99
  • May 2026 Galaxy Pass$9.99
  • April 2026 Galaxy Pass$9.99
  • February 2026 Galaxy Pass$9.99
  • December Galaxy Pass$9.99
  • January 2026 Galaxy Pass$9.99
  • November 2025 Galaxy Pass$9.99
  • October 2025 Galaxy Pass$9.99
  • September 2025 Galaxy Pass$9.99
  • July 2025 Galaxy Pass$9.99
  • August 2025 Galaxy Pass$9.99
  • June 2025 Galaxy Pass$9.99
  • May 2025 Galaxy Pass$9.99
  • 1,100 Gems2 variants$9.99
  • April 2025 Galaxy Pass$9.99
  • March 2025 Galaxy Pass$9.99
  • February 2025 Galaxy Pass$9.99
  • Galaxy Pass$9.99
  • Swishbuckler Chromaria Bundle$14.99
  • Chromarian Chromaria Bundle$14.99
  • Remi Chromaria Bundle$14.99
  • Galaxy Reroll$14.99
  • Candylar Reroll$14.99
  • Mythbound Reroll$14.99
  • Thanatos Mythbound Bundle$14.99
  • Baldr Mythbound Bundle$14.99
  • Hecate Mythbound Bundle$14.99
  • Candylar Goat T Preorder$14.99
  • Candylar Beanstalk Preorder$14.99
  • Candylar Candy Pandy Preorder$14.99
  • 2,300 Gems2 variants$19.99
  • Winter Bundle$29.99
  • 6,000 Gems$49.99
  • 14,000 Gems2 variants$99.99
None

Cost Exchange

No in-app purchases

Questions

Is Once Upon a Galaxy free?
Once Upon a Galaxy is free to download, with in-app purchases available.
Is Cost Exchange free?
Cost Exchange is free to download, with no in-app purchases.
Do Once Upon a Galaxy or Cost Exchange have ads?
Neither Once Upon a Galaxy nor Cost Exchange shows ads.

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