Depends on your cash situation. Either build one out of a wine refrigerator, a cooler, etc or look into a Nature's Spirit incubator. Check out their website, their incubators are great. In fact, Chicago Reptile House uses them for all or most of their BP egg clutches.
Homemade incubator is very easy to make and you can build it to whatever size you need. Always plan ahead. Don't build one that fits only one or two clutches if next year you produce ten. I made mine out of an old single door freezer with some 11" flexwat, 2 fans and a thermostat. This thing works great and another good thing bout making your own. If something goes wrong you have a better understanding of what it could be and how to fix it. I have 2 thermometers one on the top shelf and one on the bottom. The temps are consistently exactly the same all season long. This is really inexspensive as well. Maybe $100-125 somewhere in that range. Minifridge works well too. Good Luck