So was just browsing these hotel app websites.

I thought they would be all the same price or near enough 

Looking at the Zing Resort in Jomtien for 3 nights 

Friday to Monday 

There are price difference,no idea why ?

I used

Agoda 3061 baht 

Trip com 2872 baht 

Booking com 3206 baht 

reasons may be many : commission hotel pays to website , different type of room offered, even if of the same kind i.e Agoda offers 'standard;' room with view of pool or the street while Trip may offer the same 'standard' room with cheerful view of garbage containers or wall 2m from the window. Rooms may be on different floor , one site  made 2 dozen bookings for hotel since yesterday while other site did not have any luck etc.

I think reason why it happens is not that relevant but it pays to know that such differences exist and we can play it to our advantage securing most economical deal. Sometimes one site doesn't offer rooms in given hotel but they may be available on other site. ( my case in Sukhotai last January).

Also it pays to check more than once what prices  are being offered and if cheaper you can cancel previous deal (if you have that option) and book the same again for say , 15 $ less. 

15 minutes ago, vinapu said:

reasons may be many : commission hotel pays to website , different type of room offered, even if of the same kind i.e Agoda offers 'standard;' room with view of pool or the street while Trip may offer the same 'standard' room with cheerful view of garbage containers or wall 2m from the window. Rooms may be on different floor , one site  made 2 dozen bookings for hotel since yesterday while other site did not have any luck etc.

I think reason why it happens is not that relevant but it pays to know that such differences exist and we can play it to our advantage securing most economical deal. Sometimes one site doesn't offer rooms in given hotel but they may be available on other site. ( my case in Sukhotai last January).

Also it pays to check more than once what prices  are being offered and if cheaper you can cancel previous deal (if you have that option) and book the same again for say , 15 $ less. 

I didn't know you could cancel 

5 minutes ago, Olddaddy said:

I didn't know you could cancel 

only when you purchase that option. Quite often they quote you two prices ' non-refundable " ( final) and with option to cancel up to certain date. Sometimes that option is only few $ more then non-refundable , sometimes price difference is very substantial (Raya comes to mind).