I totally get the frustration because I went through the exact same thing when I first started my home business here in the city. I was printing out massive training manuals and the prices at Staples just about gave me a heart attack. Honestly, I spent a solid weekend driving around Chicago looking for a better deal because I refused to pay $60 for a case. I eventually found a rhythm that works really well for me and I have been super satisfied with the quality. Here is what I learned about hunting down paper:

• Costco is my absolute go-to if you have a membership. Their Kirkland Signature or even the Hammermill cases are usually way cheaper than anywhere else, like $35 or $40. The paper is thick enough that it doesnt feel cheap for clients, which was a big worry of mine starting out.
• If you dont have a membership, check out the Target near the Loop or even out in the suburbs. Their Up and Up brand is surprisingly decent. I used it for about 200 contracts last month and had zero jams. Plus, they usually have it in stock so no shipping drama.
• Check out the local liquidators or overstock shops. Sometimes places like Big Lots get office supplies from closed businesses and you can snag a ream for like three bucks. It is kinda hit or miss tho. Its all about the brightness rating too. Anything above 92 looks professional enough for legal stuff. I am really happy with how much I have saved just by avoiding the dedicated office stores... they really upcharge for the convenience.

Yep, this is the way

My approach for reliable paper:

• Costco Business Center: Hammermill 20lb is around $35/case.
• Quill: Safe shipping but requires bulk orders.