plop down

verb3

1. •
   (informal) To sit or lie down heavily and inelegantly.

   • They plopped themselves down on the bed.
2. •
   (informal) To put down (something) in a heavy way.

   • He plopped his wallet down.
3. •
   (US, informal) To pay.

   • I can't just plop down $50 for any old pair of jeans.