@ikke has pretty much nailed it.
Also worth noting that some pokemon, most of them really useful, have a free evolution from 2nd to 3rd form if they’re traded. So, if you have any friends who play and they have high level, poor IV examples who can trade you the 1st or 2nd stage of these:
Abra* Kadabra (evolves into Alakazam)
Machop* Machoke (evolves into Machamp)
Geodude* Graveler (evolves into Golem)
Gastly* Haunter (evolves into Gengar)
Roggenrola* Boldore (evolves into Gigalith)
Timburr* Gurrdurr (evolves into Conkeldurr)
- Karrablast (evolves into Escavalier)
- Shelmet (evolves into Accelgor)
It will only cost you 25 candies (or zero for the last two as they only have 1 evolution) to evolve them fully. So, even though your Level 29 57%IV traded machop might not be one for the long term, right now it will be a very good team member in all kinds of situations for a cost of only 25 candy.
Generally, this is my take on playing.;You’ll hear a lot of nonsense from people about how only 4* pokemon or 97%+ are any good, in PvE (raids, gyms, rocket battles) that’s not true, in PvP (GBL etc) it’s a little more important but not vital. IV’s make up no more than (very roughly) 10% of total stats so whilst a hundo is better and gives you better value for dust/candy, it doesn’t make that 65% useless. I’m L50, have been playing for years but some of my teams still have poor IV candidates , simply because it’s not worth spending the dust to gain a few fractions of extra performance or because on that particular Community Day I could only find a shiny with poor IVs.
You’ll be tempted to spend dust and candy early, because it can be tricky to be competitive in your first few months. Wherever you can, don’t. T3 raids can be a useful source of various counters, as can purified shadows (instant L25), make do for now, you’ll be rewarded later when you can start to really power up your good candidates. Lucky trades wherever possible are great for saving dust, so again, if you have a local group see who can randomly trade you their excess stuff, I’ve got loads that I keep just in case people need a few IV rerolls.
If you don’t have an active local community, try and join a raid group too, so you can hit more raids and win more often. Most areas have a facebook/discord group, I’ve got a local group and an international group and it’s unusual if we don’t manage to get numbers to raid when we want to.
Keep an eye on future events so you can plan what you do - eg, Saturday is Community Day, so don’t be evolving any Samurott until then.
Apart from that, enjoy it, it’s a game not a job, although sometimes it can feel like one.