EE new deal. Any advice what I should be aiming for?

Hello and thanks for looking.

Just noticed my contract is up with EE so will try and negotiate a better deal if possible.

I'm currently getting unlimited mins & txts and 100 GB data (4g) for £20.59.

Has anyone else negotiated themselves a better deal lately? If so what deal are you on now?

I've seen some Three deals with unlimited everything for £15, do you think they'd price match?

Grateful for any help, thanks

Edit: I'm after SIM only btw