Hey @priceern - Thanks for messaging us here!
There are a couple of options that you could probably do with.
If you're happy with your current phone, a Sim Only Option here may suit your needs for the interim. These are Month-Month Options.
Another option is to proceed on a 12/24/36 month option with another handset. Those handset contract options can be found here.
You can also message our Sales team via the My Optus App and they can tailor some options for you, depending on your needs.