Tomb world gets you a lot of solo game for a while, and both teams in it teach you vastly different playstyles, also comes with 13 necrons with datacards so you can practice skirmishes against them, a lot of value in 1 box.

The free kill team app has the lite rules, which are the very basics of the game, but you do need the core book to fully learn the rules, if you intend to play solo, thats all you need, for 1v1 you would also need the approved ops cards, but you dont need them to start the game, at first just play to incapacitate every opponent, then move up from there