Will my portal show budget airlines as well as the big well known airlines?

Yes, in most cases it can, but budget airlines do not always arrive through the same connection as the traditional airlines, so they usually have to be switched on as an extra supplier rather than appearing on their own. Once that is in place, a low cost flight sits in the same result list as any other flight and your customer does not need to know where it came from.

There are a few things that behave differently with these airlines. Their headline fare is often the bare seat only, with bags, seats and sometimes even a card fee charged on top, so the first figure your customer sees can be lower than what they finally pay. A good portal shows those extras before payment wherever the supplier passes that detail back, but not every budget airline sends it in the same level of detail, so how much your customer sees varies from one airline to another.

Be aware too that changes, cancellations and refunds on these tickets follow the airline own rules, and those rules are usually stricter than on a normal ticket. Some of them do not allow agents to make bookings at all in certain countries, so coverage depends on where you are selling and which suppliers your plan includes.

The sensible next step is to ask which low cost content is already included in your setup, then run a test search on a route where you know a budget airline flies, so you can see what your customers will actually get before you promise it to them.