The first day of next season is when u are a token buyer.With ur 17t u would be very lucky if u buy a player the most 2(in my opinion if u have a crapy server u wouldnt buy none..u will loose all ur tokens).
I will tell u my story after 5 levels.1-2 bought tokens (80 per season).No use to waste money,cause the problems of the game are very huge,decided not to buy tokens for 3-4 level.That cost me a bit in level 3 ,did ok in l4,and pretty good so far.
My team is gonna be so and so for next level and have to decide if i will go back in a 80t strategy(i think 80t per season is ok to have some extra fun ,win league and Cl and have a very competitive team).
So in 3-4 levels i bought all my players almost before the end of the seasons.
I had no bidding wars,and with 1-2 t i manage to set my team for the next level.
Its a good choice to replace most of ur 3* players with 5* which will be 4* next season.
or even ur oldies 4* with 5* which will be 4* again next season.
You need 6-7 main players for me GK,2 DCs(with second role),2 MCs,1 AMR-L(if u play with wings) and 1 ST.
If u have a mix of 4-5* in the above and some good 4* players for subs,then u can easily replace all ur 3* players during the season with 4 or even sometimes with 5*.
Hope that i help u