day 1)
Left rocket 3
Launcher 1
get lucky and get left rocket 4 on second day, the next days you should buy (in this order)
More left rocket
More e-Rocket
More Launcher
More Band
On day 5: don't buy anymore left rocket!
This game is doable if you're kind of intelligent and you now what you're doing. If you don't know what you're doing, (and you're just guessing) it will be hard to finish this game :P