I was raised to be a "bargain shopper" across the board: food, clothing, cars, and more recently that has even leached into areas of my home design. But, is that a bad thing? No, I don't think so.
For my own personal style, I like to mix and match the new and old. One surefire way to make a room feel elevated without spending tons is to pick one quality piece for each room, and make it a centerpiece at that, for extra credit! As an example, if you look in my living room, I have a coffee table that I bought off of Marketplace that I refinished (for under $50). Next, my area rug is under $400 (it's 11x14). Lots of my random decor is from Tuesday Morning, Home Goods or Hobby Lobby. I do have some antique books mixed in, as well as a vintage champagne wooden sign, to keep the space from feeling cookie cutter. One of my "side tables" is an antique dresser that has been painted and distressed-the thing stinks as far as being legitimately usable (the drawers stick), but it makes me happy...The area where I didn't skimp was my white couches-they have been not only a good investment, but I feel they elevate the room. If I had chosen a cheaper couch, the fabric would likely be showing its age, and it would bring down the style of the room.
Another example is in my dining room: our dining room table has seen better days-yes it's antique, but not necessarily in the best of ways (think missing pieces in the legs, scratches on the top and a bit wobbly). BUT, add in a nice tablecloth and staging and you'd never know. On my walls are generic pieces of art here and there (with two original pieces mixed in). The piece that elevates the room is my grandmother's 1840s china hutch, in mint condition. If I didn't have the one piece to elevate the design of the room, it wouldn't feel as special.
So, your homework assignment: wander through your house (hey, you're working from home anyway!), pause in each room and note how the room makes you FEEL. Then, identify which pieces in the room you are most proud of and if that piece helps to elevate the feeling in the space. Don't be afraid to move things around in your home. If you're stuck, give me a call!