questions regarding ordinary visa and airasia flight (covid))

hello,

when i arrive at phon penh airport, i ask for a ordinary visa, pay 35$ and get it, right? no invitation letter required? or how much they ask in thb? should i change money first?

i booked a flight with airasia on the day my thai visa expires, from don muang to phnom penh.
does airasia require an antigen or pcr test for boarding? or insurance or return ticket...etc?

afaik cambodia does not require anything. ust an antigen test on arrival..

(iḿ NOT vaccinated)