What is your progression plan?

My plan so far:

1. Get Kroguard
2. Headbutt stuff
3. Gold/Outlaws
4. ???
5. Profit

Just use any melee build and profit. Human vanguard, asari adept, most krogans, can easily do gold with crap guns as long as you have the right build and the juggernaut shield. From fairly low levels too, on the vanguards just max charge and fitness and you are ready to go. Don't even need max charge tbh.

This...

I'm maxing out commons then uncommons and so forth. Haven't quite got all the commons yet but I've unlocked every uncommon char and a few guns from basic packs. Have Asari Sentinel V, Kroguard II, Carnifex II, etc. Makes it a lot cheaper than trying to go from top to bottom.

Max commons. Get kits silverready ( depending on weapon, between level 6 to level 9 at the mom ).
After that max uncommons. Go gold. Then Rares. Hopefully plat is released by then, if I can go it ofc. And last but not least, URs.

All the while complaining about incompetent and in most cases even competent pugs ( because they outscorewhore me ).

I concentrated on basic 5k packs until my commons were getting close to max then switched to the advanced 20k. The advanced packs usually give me a common along with an uncommon so they will still get maxed.

In fact I only need 5 weapon mods to max my common items. I love seeing Xs next to everything. Next will be the uncommon. I'm being fairly methodical but occasionally indulging in an expert pack which usually disappoints. I don't think I have any ultra rare items yet.

I am playing my biotic boom Asari Adept IX on gold with the Raptor. She holds her own just fine and can even carry against Outlaws so getting credits is not a big problem.

Not doing much in MP for now, waiting to see what bioware does to it or plans to do with it. I've been playing the SP in the meantime, keeping mission funds running so I can buy stuff from the item store, just to kinda-sorta keep up.

I agree that buying a fair amount of Expert or Premium packs fairly early is a good option.  Getting a few viable guns helps out a lot in the early game, but I would suggest going back to the bronze and silver packs sooner rather than later.  It's not about the weapons trash; it's about getting those common character cards maxed out.  There's a world of difference between a level I and a level X character, and having a nice filled out build will make it so much easier to farm gold.

In terms of packs maxing basics isn't a bad idea, but mix in some higher tier packs (50 or 100k) as well for a chance at some not trash guns I'd say since those are gonna be at least gold and well it's just a bit more fun to buy basics if you occasionally mix in one of those packs as well. (vanq or talon for example). It's a good idea since you'll get a lot of consumables to do gold with, a lot of x tier mods and level x classes with many points to spend. Not a must though especially not if you don't fancy the common classes but a pretty good idea.

After you max basics for your own sake plz move on to 50 or 100k packs, literally no reason to max out uncommon stuff unless you really want an uncommon class or a certain uncommon weapon mod to x. It certainly won't make you get more gold cards from the expensive packs, you'll get 1 or 2 regardless of if you have maxed uncommons or not, if you have them maxed you'll just get extra consumables. Also you'll get a lot of uncommons from the higher tier packs anyway so chances are you'll max them out before your gold cards by doing this even if you skip advanced packs.

1) Get carried on gold
2) ???
3) Profit

I don't know about others, but I'm going to continue to farm gold like a noob with melee female vanguard (because im a female girl in real life as my avatar clearly shows). As long as I continue on my current trajectory, I should have all my rares maxed out within a month or maybe less, and then the real fun begins - the hunt for the remaining ultra rares. Can't wait til all my rares are maxed out! Looking forward to using the equaliser 10 with max level mods eeeeek.

In terms of packs, buy only basic packs til you max out all of your commons. This took me just three days roughly. Then after that, move straight to premium packs, don't even bother with advanced packs or expert packs, unless you really need to get one/some of your uncommon characters to level X as fast as possible.

Avoid expert packs completely.