Just pay $100, that's it. Employer's responsibility is to send the helper back by providing an air ticket to Manila and $100 allowance for meals and transport.
I think your maid didn't buy the ticket yet. She just want to "大你".
Last time I terminated my maid, she told me she have brought the ticket already. Then I told her according to the law, I have to give her an air-ticket insteads of cash. ( That's true! You can check w/ the labour dept. ) Then I brought the cheaper one for her and give her $100 for food and travelling allowance.(because she can arrive home place in the same day of the termination)