It's definitely not the typical f2p game. It has so much content that you can access for free that it feels like a steal.
Some people ask in wonder why it's a f2p game sometimes.
There are some bad parts, like the bugs and of course the fact that it's a P2P game just like E.D. but i can live with that. You can limit your ping to the P2P connections (matchmaking) from options to a maximum of 100. Also the bugfixing is much faster, they patch the game all the time, even multiple times per day if it's needed.
I did spend about 4k+ platinum ingame, half of that was given as a present from someone who stopped playing. I spent most of it on cosmetics/ship interior decorations (there's a lot of them and bobbleheads) and slots.
A part of it was spent on progress stuff like
Forma bundles because they are a bit slow to craft for my gaming needs or drop/affinity boosters because i wanted to level/access endgame faster (you level by leveling different types of weapons/frames/pets that you craft with drops).
The biggest part in Warframe is RNG, it has much more than E.D., so i guess the Elite players that don't like Engineers wouldn't like Warframe also. I mean i farmed
Kuva for a week straight with a drop booster and spent it on a few hundred
Riven rolls and didn't get what i wanted, but i enjoyed doing it. There is RNG in everything, from mod drops to weapon/frame blueprint drops.
Imagine the ships in E.D being made of parts and RNG involved in getting their craftable blueprint (which you craft with RNG drop materials) - something like that.
I like RNG so it's fine by me.
Like "Navigare Necesse Est" said, you can progress without spending anything (it's a bit slow tho). The only thing need to spend on is weapon/frame/pet slots, but you can get platinum easy by
trading.
That being said, the most thing i like about it is the different planets you can go on, or space derelicts/bases. They really nailed the feeling that you are right there on that X planet or place. The landscapes are amazing and the (few) asteroid rings you can see feel more
realistic (btw they are supposed to stand still like it is in E.D? - no idea about the science of it).
Also the community is much better from the one in E.D. from my point of view.