Of the 2 Kreyol words for money, "kob e lajan", which is more popular? Mesi.

Both, kòb and lajan, are used pretty consistently.
Other terms that you will hear are lamama, tyotyo, grennbak, poud kafe
and for change, we say monnen in Creole

Haitian Creole ↔ English Reference, Look up Haitian Creole and English Words

what is money in creol

money → lajan, kòb, lamama, tyotyo, mago, grennbak, and even poud kafe :)

cents → santim, kòb
10 cents → di santim or dis kòb
50 cents → senkant santim or senkant kòb
$1.75 → yon dola swasannkenz santim or yon dola swasannkenz kòb

change → monnen

Do you have any change?
Eske ou gen monnen?

Give me back the change.
Remèt mwen monnen an.

Ask me anything