At LAX, there are free baggage carts upon international arrival at TBIT. You can keep the cart after going through customs and bag recheck to use it as you walk to the terminal for your next flight. You must cease use of the cart before going through TSA security in the new terminal.

For domestic arrivals, there should be a way to pay to rent a cart, probably for about $2, for example in the baggage claim area of the terminal for your arriving flight.

BTW, I was ready to guess that OP's connection was at ORD. Their international terminal is T5 while T2 contains domestic flights and some international departures.