What pack should I get?

My suggestions are packs that make the game feel more life-like. I tend to play realistically and with families.

Growing Together
Parenthood
Seasons
Cats & Dogs

Cottage Living and Knifty Knitting are the two I love and use the most though, but that’s because I can live out my Cottagecore dreams.

What is your play style? Do you like occult game play? Do you like family game play? Raising children?

Considering you’re just starting from scratch, I suggest the following:
Seasons
Dream Home
Tiny Living
Oasis Courtyard
They will go perfectly with your Base worlds.

Then later you can decide what theme you want & get the packs that will go with that theme.?

Yeah if price is a consideration:

$5 Kits
$10 Stuff Packs
$20 Game Packs
$40 Expansion Packs

List of packs.

https://www.ea.com/en/games/the-sims/the-sims-4/store/browse

You can get most of the older EPs on sale. I would recommend Seasons and/or Get Together. Both bring a large amount of gameplay.

i really like Cottage living also seasons and cats and dogs

I've seen quite a few tier list on what packs are best to buy and why on YT. Check them out:
https://www.youtube.com/results?search_query=sims+4+tier+list+

I don't think this years summer sale has happened yet so you can always wait to save money.

How impatient are you? With limited funds I would recommend to wait for a sale. EP often go off 50% during a sale so then you could get an additional pack for the same money.

For the rest it depends on what you like
Seasons : gives a general feel of years passing and makes the world alive
Get together is great for the basics. You get a big world with plenty of lots to fill. The club feature allows to easily get together with groups of sims
Growing together and parenthood add more depth for raising families.
Realm of magic, werewolves and vampires are essential for playing occult or fantasy themed stories
Cats and dogs or cottage living are very fun if you like to focus on animals

Where are you based? If you have access to CD Keys or Instant Gaming you can purchase discounted packs.

It's difficult to recommend particular packs without knowing your gameplay style.

If we think 1 EP= 40e

I would wait sale since eps and gps are often 50% off and you could get 2-3 packs then and have more options and things to explore

I still feel like Seasons is most essential for me with EPs but its more so background thing making things more lively less so something with big amounts of stuff to explore

if you had two packs in sale you could then pick something more themey or activity based for the second option

or add couple gamepacks that interest you

or indeed with 50% off you could get 4 game packs for the ep price which does sound like more fun to me than just one ep

but then again I do like occults and they are often in GP so theres that :lol: