Sims 4 DLC are too expensive

welcome to The Sims 4 is all I can say.

On another note. Buying it all is not worth it, at all. You need to be selective or you end up with things that makes your experience worse than just owning base game (in my humble opinion). 

Speaking as a person who owns everything from Sims 1 onward I think I can weigh in on this. If you would like a suggestion on packs that would be good just as basics I'll give you a few suggestions. 

Basics Beyond Base 

• Cats & Dogs 
• Discover University
• Get To Work
  • Pros - Added the Baking Skill 
  • Cons 
    • Added Baking but never, ever updated it
      • Left obvious Baking recipes in Cooking 
      • Made it a pain in the B**t to find specific recipes between the two 
    • a bit limited in its scope, kept most thing vague, added nothing new over the years and then had to create a whole new pack to Update it 
  • Complimentary Packs 
    • Dining Out 
      • Cozy Bistro Kit 
      • Cool Kitchen Stuff
      • Home Chef Hustle 
• Get Together 
• Laundry Day 
• Seasons 
  • Complimentary Packs  
    • Spooky Stuff Pack 
    • Paranormal Stuff 
    • Holiday Stuff Pack - I think was free 
• Spa Day

If You Like the Occults 

• Life & Death
  • Pros
    • Funerals 
    • Improvements to Ghosts 
  • Cons 
    • The Raven isn't much of a Pet 
    • The Bell tower is a Rabbit Hole and not very interesting to mess with more than once 
      • Missed Opportunity for Bell Ringing Activities 
    • No new Community Lot Designations for 
      • Purchasing coffins and making a will in a town square feels super disrespectful considering the subject matter
    • They should have added a Graveyard in the Vampire's Town, Forgotten Hollow at least 
• Paranormal Stuff - Yes I listed it twice. It's Pretty Good
• Vampires - Almost perfect pack
  • Cons
    • Vampires should abhor Silver
    • Should have gotten an Update to the Town when Life & Death brought in Cemeteries
    • Eclipsing Fog from Sims 3 should have been brought in as a Vampire Power 
• Werewolves
  • Cons
    • Silver should be a no-no for Werewolves
    • Should have been able to extend the muzzle & ears just a bit, made them little more "The Howling" a little less "Furry"
• Crystal Creations 
  • Cons 
    • The jewelry designs were a bit woo-woo and they should have added a bit more high end looks 

If You Like Travel 

• Snowy Escape
  • Pros
    • Has Japanese Culture 
    • Skiing & Winter Sports 
  • Cons 
    • Not Enough Japanese Culture 
      • No Teppanyaki or Sushi Counters with NPC Chefs just the Kiosks 
      • No Sleeping Futons
    • Winter Sports would have been better in a European setting dedicated to these activities  like San Moritz
    • Missed opportunities 
      • Ski Chalets
      • Apre Skis Parties 
      • Another good spot for Sauna & Polar Bear Swimming 
• Outdoor Retreat 
  • Cons
    • It's small
    • You cannot swim in the lake
    • No Bigfoot 
    • The Cabins are ugly on the inside
    • Should have been refreshed 
• Island Retreat 
  • Pros 
    • Its beautiful
    • It has Mermaids 
    • Sea Turtles
    • Snorkeling 
    • Boats
  • Cons 
    • Mermaids should have had a tiered power system 
    • No Hula, this pack absolutely needed it 
    • It should have had the Coconut trees be climbable to get the coconuts
    • No Scuba Diving
    • No Surfing
    • No Deep Dive Spots 
    • Dogs should have gotten Life Preservers and chances to be out on boats 
• Horse Ranch - If you really want Horses, otherwise without an open world it really wasn't that interesting. 

Packs you could entirely skip without really missing anything 

• Eco Lifestyle 
• For Rent 
• Strangerville 
• Dream Home Decorator 
• Star Wars Journey to Batuu
• Moshino 
• Perfect Patio
• Most of the Kits unless it has things you are keen on 
  • Modern Menswear is NOT good 
  • Carnaval also not great 
• Lovestruck 

If you can't pay for Sims, then you can't pay for Battlefield or Silksong either. You can check out the sales, the EPs are frequently 50% off, and bundles also seem like a good offer. I also hear that Instant Gaming website has very good prices for Sim packs, better than on the EA website.