One of the nice things about spawning Betta splendens is that there is not a lot of equipment that is required. And certainly the equipment that is required is pretty basic not a lot of it expensive. You can get fancy and buy more, but good care and basic equipment will make up for good equipment and bad care every time.
We have net several folks recently involved in the hobby of Bettas who have poured a significant amount of money into the process and have failed. We have also met folks who have used scavenged materials and used tanks who have succeeded very nicely. Have the resources to buy "the best" equipment is not a significant nor strategic asset in this segment of the aquatic hobby. Patience, care and experience is more important than having money to buy the "the best" equipment.
We like to provide a 10g tank for the fish to spawn in. We have used smaller tanks, but find that the 10g allow us to keep the spawn in the same tank for as long as a month depending on the size of the spawn. Smaller tanks forced us to move the fish in just a couple of weeks, when the fish were still quite small and probably fragile. The tank should be covered. We use two sheets of glass. One to act as a lid and one that is kept in place. The larger piece has a corner or two clipped off to allow for the heater cord and the air line to pass through and into the tank. By the way...in most locations, 10 gallon tanks are cheaper than smaller tanks too!
We like to use small sponge filters in all of our spawning tanks. The air is set on a low setting as Bettas prefer to spawn in a fairly calm environment. How low do we set the air? It's set low enough to disturb the surface is a very minor way (if at all) but yet keep the bacteria colony in the sponge filter alive. As the water level is raised post spawning, the velocity of the air is increased to provide for additional mechanical filtration capacity.
We have witnessed male fish seeming confused in spawning tanks with the air bubbling too vigorously. It's been almost as if the fish were confused by the large bubble, possibly mistaking them for a bubble nest in progress. When the air was turned down, the fish were under the nest structure within the hour, building their nest as if they had read a book.
The heater should be submersible one. We prefer to use a 25w heater. We use a brand that is only 6 inches long, making it nearly perfect for the application. We set the heater in advance of adding the pair and test it in the tank to make sure that the water is 82F before the fish go into the tank. Once the heater is set, we use it over and over, and between uses, unplug it and hang it on the wall...the temperature stays set (although we continue to test the water prior to the addition of fish...stuff can happen when the heater is hanging on the wall)..
A glass chimney is a very useful tool. We like to use a chimney that is designed for a candle lamp. It has straight sides and is 5 inches in diameter. We also use a chimney designed for a kerosene "hurricane lamp." It has curved sides. We prefer the straight sided variety. One can use a jar, but will quickly find out that releasing the female is a little tricky and getting her back in the thing in the case of a "situation" will be a real chore. With any of the chimney tools you can lift the glass from the tank without disturbing the bubble nest and if the female needs to be returned to the chimney, one can frequently do so without using a net by sliding the glass tube over the female. Some folks have found acrylic-like tubes and use them instead of glass. We still prefer the glass ones because they are easy to clean (and sterilize) and do not scratch over time as do the acrylic ones.
Even though you think you have one, a good net is important. We prefer to use a "fine" net of some sort as opposed to a "fast catch" type. The "fast catch" type are usually a coarse green material and while we have no evidence that they hurt the finnage we just feel more comfortable using a fine textured net.
A thermometer is a good device...82F is a perfect temperature. Just a couple of degrees either way can make a huge difference in the size and vigor of the spawn...with negative impacts...not good ones.
The last piece of equipment that we use we make from a white plastic grocery sack. We cut a 4 inch circle from the white plastic and place it in one corner of the tank for the male to build his nest under. We know you have read about cutting Styrofoam cups in half and we have tried those in the past. Our cups always leaned this way and that and the male sometimes built his next 1/2 in and 1/2 out of the cup. We have had superlative success with the grocery sack...and you don't have to run out and buy Styrofoam cups...but if you do run to the store to get the cups ask for plastic (rather than paper bags) and you will have the sack to cut the circle from later.
We like to have all the food stuff that we will be needing for the conditioning of the breeding pair and the subsequent fry in our shop and ready to go prior to starting the process. The fry develop at a fairly fast rate and finding the time to order "stuff" and have the supplies shipped sometimes can't happen soon enough for the fry...and they die. Death is never a pleasant thing, but with our luck we know that if a spawn is going to die we can be assured that the spawn was from our favorite fish and those fish are never going to spawn again. It's a theory based on "Murphy's Law." It's best to play like a Boy Scout, use the Scout Motto and "Be Prepared." Have the food cultures in your hands prior to starting a spawning process.
We use live food to feed young Bettas primarily Vinegar Eels, Microworms and Baby Brine Shrimp to feed new fry and until they are about 1/4 of an inch long. At that time we introduce them to Grindal Worms. When the fish are large enough to be jarred (about 1 month of age) we begin feeding them frozen bloodworms in addition to small (or chopped) whiteworms , red worms or blackworms.