Buying solid hardwood boards becomes more expensive as you try to buy a wider board. The wider the wood, the more the probability that there will be knots and defects. It's logical that a wide board would cost more.
If a pattern calls for a 3/4" board that is a foot square, for example, the cost of a clear piece of wood 12" wide may be quite high. You can buy a 1x3 that is 6' long for much less money. This can be cut into 5 pieces which can be glued together to give a clear piece of wood almost 14"x14". And for considerably less than a nice 12"x12".
Of course you have to buy a clear, unwarped 1x3, just as you would have had to choose a nice wide board, but the good 1x3 is a lot easier to find. The wider the board the more likely it is to be warped. You may want to match the grain patterns as well as possible so there will not be obvious grain or color lines where boards join. If grain mismatching will hurt this project, then you probably can't splice 1x3s to make this project piece.
There is a bar clamp made especially for edge-gluing boards. You can see what these clamps look like at your tool shop. There will be photos of the clamps put in a little later. And you can even save money on bar clamps by buying the same clamps, but made for mounting on a 3/4" pipe. This is a very economical way of making clamps that can handle large or small projects because you can use pipes as long as you wish.
The system consists of a bar with a sliding clamp at one end. The other clamp is fitted with threads. You would need two bar clamps, one placed 1/4" of the distance from each end of the wood to be clamped. Normally I'll want the edges of the boards to be undented, so I would use strips of scrap wood against the clamps.
The boards must rest evenly on the bars and remain there when tightened. Therefore test that everything fits correctly before gluing. Tighten up the wood in the clamps, then check to make sure all pieces are resting on the bar and didn't bow up.
Check to see that there are no gaps on top or bottom where the boards meet each other. If everything is OK, loosen the clamps and glue. But if there was bowing or gaps, the edges of some of the pieces are not square or not straight. Use a square to find which piece(s) causes the problem. Put it through the table saw, shaving the edge that will be glued. While cutting, maintain constant pressure to keep the board against the saw fence.
Remember that most wood glues set up in five minutes, so don’t glue longer than that. If necessary, clamp the first 2 or 3 boards in place until the glue is set (15 minutes or so) then add the rest of the pieces.. There are now wood glues that set up slower.
While the wood is clamped, wipe away as much squeezed out glue as possible to save later sanding. In many cases I will remove the wood from the clamps after a half hour or so and scrape away the half-hardened glue, then put the wood back in the clamps to cure.
Tighten the clamps firmly, but do not use a tool; don't tighten more than hand tight. If the clamps are more than hand tight, you could squeeze out so much glue that there isn’t enough left to hold the wood securely.
Today there are many variations of a bar clamp, especially smaller ones. These can be be closed by sqeezing a handle. The clamps in many cases can be reversed on the bar so the device can also be used as a spreader.
Clamps are another tool that can be purchased from a tool dealer that has heavy discounts. The discounts are a large percentage, yet a faulty clamp is not critical. A faulty table saw, for example, is critical.