Not sure if I read this correctly, but it's $8 cashback for all new customers
And currently Lyca has discount on Unlimited S and 20 so should be $5, $3 profits.
Moderator's update
We asked TopCashback to clarify whether these unlisted plans (unlisted on TopCashback) are eligible for the $8 new customer cashback. It turns out that the eligibility is not determined by TopCashback but by Lyca Mobile, and they have not heard back from Lyca Mobile about these unlisted plans. TopCashback expect an answer after Christmas.
Our advice to users is that you should buy a Lyca Mobile plan if you need a new mobile plan and one of these meets your requirements; you should not buy one if you expect to make a profit.
They sign you up for an auto recharge which does not show in your account, but when it comes the time of expiry it does not expire but bills you again. Very hard to get that payment refunded. I am still fighting with them for mine.