In Western countries it is customary for people to split the bill when having meals. Of course on special occasions, or if someone is feeling especially generous, one person might pick up the entire tab (tab = a record of things ordered by the customer. Pick up the tab = pay for the tab).
So if you really want to pay for a meal, or pick up a bar tab, what are some common expressions?
“It’s on me” is the most common. The “burden of paying” is on me, not you.
“It’s my treat.” is also very common. It’s my treat (free meal) that I am giving to you.
It can also be used as a verb “I’ll treat you to dinner.” This often gets shorted to “Let’s grab dinner. My treat.”
“I got this.” is a much more casual expression, said as you pick up the check from the restaurant table. It means “I got this taken care of” or “I’ll handle this.”
You can use any one you want, there is just a small nuance of difference.
“It’s on me” is like you are doing a favor for the other person.
“It’s my treat” is like you are giving a gift to the other person.
“I got this” is like you are saying that the amount is small and no problem for you.
There is also usually not too much arguing if someone offers to pay. One refusal is plenty.
A: “It’s on me.”
B: “No really, it’s fine. Let’s split it.”
A: “Nonsense. I insist!”
B: “Ok, thanks.”
It’s not rude at all to accept the offer right away. In fact, if you don’t, you may talk yourself out of a free meal.
A: “Don’t worry about the check, it’s my treat.”
B: “Really, you shouldn’t. Let’s just split it.”
A: “Well ok, if you insist. Let’s each pay half.”