When registered with Shift, you automatically start with a free plan and you can always upgrade to a higher plan or move to a smaller plan. On clicking the profile logo to the top left of the account, click on the subscription plans option.

You can now see all the plans and the features being offered in each plan and the cost of the plan per month. However, If you wish to pay for a period of 6 months or yearly all at once, then check out the bundle packs. Click on activate to initiate payment and switch to the chosen plan.