The bonus changes on total tokens sold, not on the amount that you as an individual buy. So basically what matters is when you buy, the earlier the better. It's in the table that's been linked in this thread, and also on the token sale page of the website: https://www.fintrux.com/tokensale.aspx
The pre-sale starts at: 5:00PM UTC, 07 Dec, 2017 ... which is 1 day and 21 hours from the time I post this Again this is on the token sale page of the website: https://www.fintrux.com/tokensale.aspx
Pre-sale ends at: 5:00PM UTC, 21 Dec, 2017 ... i.e., after 14 days.
You can register for pre-sale on the token page of the website