Slash Tabs ?

Question: every new League i have to buy new Slash Tabs because i don't have Slash Tabs now from previous League ? i'm new player

Stash tabs are an account purchase.

If you buy a bundle you would have 10 on every league (excluding custom leagues with the no stash mod)

If you play in the new league content you will start with those 10 tabs.
At the end of the league all tabs with stuff in them are transferred to one of the permanent leagues as remove only tabs (so standard would have 10 tabs + remove only tabs)

The only thing you need to look out for is that IF you play on the standard league remove only tabs are converted to fully functioning tab first.

ok but the problem is before i have 3 Slash Tabs and 1 currency stash tab, i stop to play for 6 months and now i dont have them ?

If you bought a currency tab, you should still have it (assuming you are logged into the same account).

Are you sure you don't have it? If it migrated from a different league, it might be off to the right and you'll have to scroll over there to see it.