For 100million, you could buy the world!
Sell:
DEF:
Monreal
Jenkinson
Vermaelen
MID:
Arteta
Cazorla (He looks good but his stats decrease so quickly)
ST:
Bendtner
Podolski
Buy:
DEF:
Balanta
Doria
Jonathan Silva
Clyne/Serge Aurier
Luke Shaw is expensive but worth it too.
MID:
Pugliese (On a free - approach to sign)
Andrija Zivkovic (On a free - approach to sign)
Vela (3.4million buy-back clause)
Lucas Romero
Goretzka (if you can get him)
Florenzi
Bernard/Rotariu/Ocampos for the left.
Sami Khedira or Claudio Yacob could be good cover too.
ST:
Volland (12.75million release clause)(easier to get roughly, 2 weeks in)
Timo Werner (if you can get him)
Gabriel Barbosa
Donis Avdijaj (On a free - approach to sign (if you can get him)
Benzia and Vietto are also other options.
So your best team(s) would be:
Szczesny
Sagna/Aurier - Koscielny/Doria - Mertesacker/Balanta - Gibbs/Silva
Florenzi/Flamini/Romero - Ramsey/Goretzka
Walcott/Chamberlain - Ozil/Wilshere - Rosicky/(Bernard/Rotariu/Ocampos)/Vela
Giroud/Volland
You can obviously mix and match etc.
Just a few suggestions! Hope it helps.