I agree a good clean and declutter helps a lot. end of season clearance pillow covers update looks for a little money or redo picture frames update. repurpose.. I found a woven piece that one kid did in a class that was like a scarf but thicker ..now is a runner on my coffee table. the colours match the couch and give the room a little pop of colour.You can do a lot of little projects for $20 or less. For example, buy a can of paint. Sunlight light bulbs. Replace broken or cracked wall switch plates or outlet covers. (or just clean the ones you have). Floor mats near doors to collect tracked in dirt. Put down a pretty area rug. Upgrade drawer and cabinet pulls. Put shelf paper in cabinet drawers and under sinks. Replace the caulking in your shower/tub area. Buy a few small house plants and watch them grow. Put bulbs or perennials (the ones that come back every year) into your garden. If your windows have a lot of layered paint on the glass, get a scraper and clean them up. Use scented candles or air freshener (or just open a window). Get a throw for the couch to add some color. Replace pillow covers with new ones. Use a table cloth. Change the filter in your ventilation system.
But really, nothing improves a home like a good thorough cleaning.