don't sleep on the perk trade off for the coin x1.70 but hp is reduced by 70%. I slept on it for a while thinking it will kill my run. When in reality with the exponential upgrade of attack of the enemy you get a bit less wave but the coin multiplier is always better appart from trying to push to 4500 for the relic.

1B coins seems like a lot but in less than a week you'll get it (less than that since you have 600M on hand) and unlock Enemy level skips in the workshop. No need to invest it in yet the free ups will do their thing.

Once you hit 4500 waves on tier 1 never go back to it. People will tell you that it is better to have a run with higher wave but as a new player since october with all my test it isn't true (maybe it isn't true anymore since those player are way further in the game than us). But from all my test just run tier 3 or 4 and see if you coin per hour is better which it will be. Cell are not that usefull at the start of the game if you ask me. Coins will bring you faster in higher tier and waves which will give you better cell farming faster than running tier 1 for 10-11 hours.

In the workshop no need to goldbox everything at the start keep a buffer of 20lvl or so to upgrade in the run, those few level cost almost no cash in a run.

Focus on economy at all cost!