Basement refinishing varies greatly upon what you are trying to accomplish. If you are trying to finish it to become a rental basement, the cost will be much higher than finishing it to be your game room. A very general estimate for a basic remodeling is $40 - $60 per square foot of your home. This means that for a space of about 500 square feet, the estimate could be anywhere from $20,000 to $30,000.
The estimate of $20,000 to $30,000 is dependent upon putting up walls and leaving open spaces. This also takes into account an affordable floor and not very many upgrades. If you want hardwood floors and many built-in cabinets, you will be on the higher end or perhaps even more than the $30,000. If you want a basic floor and wall and ceiling, the final cost may be less.
If you are able to, doing the project yourself can save you up to half the cost by eliminating the labor. You can also affect the bottom line by planning ahead. With a floor plan and proper preparation, you will be able to do the project with the least expensive materials and on your own time. Supplies alone range approximately $10 to $25 per square feet, saving you as much as half of your original cost. This would reduce the cost of remodeling that same 500 square foot area to as low as $10,000.