Bearded Dragon having seizures

Question
I have a about 4 month bearded dragon. About a month ago I was laying down with him and all of a sudden he jumped off and he ended up having a seizure. When he stopped I picked him up making sure he was ok. After about a week I noticed he was acting a little sluggish he eats normally but also when he eats it's really hard to describe it looks like he is about to eat a worm and he can't seem to open his mouth like its stuck but then after a while he can open it and eat normally at first I though my UVB was not working and he could have MBD so I took him outside for about 30min he liked the sun and seemed happy but he still acted the same when eating and everything he's active he likes to run around. But yesterday I was laying down and from the corner of my eye I saw him fall and have another seizure when I ran to him he stopped and I picked him up he was breathing but would not open his eyes and seemed stiff then he finally opened his  eyes but seemed tired I'm planning to move his basking branch lower but that's where he basks and I don't want him not getting the proper temp if the branch is lower I wanna go to a vet but idk if theres much they can do does this seem like a MBD problem I wanted to buy a newnUVB just in case but they're a little expensive so idk if it's worth it can seizures affect the way he eats or move. Do you think he may have MBD and that's why he's having the seizures. Please if you have any opinions you may think of or any other details please let me know. Thank you so much.

Answer
MBD, which is actually 'secondary nutritional hyperparathyroidism', is caused by a lack of vitamin D3/UVB light and/or calcium in the diet.  In other words, it's a condition caused by hypocalcemia--low blood calcium.
If your dragon is having seizures, which could be caused by hypocalcemia or could have another cause, take him to the vet!  They most certainly can treat his condition, particularly if it is nutritional.

Check your husbandry.  UVB fluorescent lights must be no more than 8 inches from the animal to do any good.  UVB fluorescent lights must be replaced every 6 months.  (The new mercury-vapor reptile lights may be a better choice, as they throw UVB further, and double as a heat lamp.  They need to be replaced every 3 years).
ALL insects in the diet must be supplemented with calcium, as crickets are too high in phosphorus.

Bearded dragon salads must consist of nutritious, high-calcium greens that are relatively low in oxalates.  (No lettuce, no spinach or cabbage, no broccoli).  Definitely review a proper bearded dragon diet.

Young bearded dragons are very susceptible to nutritional deficiency diseases, because they grow so fast.  At 4 months of age, dragons are still eating insects 1 or 2 times every day, in addition to salad.  Prompt veterinary attention is your best option for a diagnosis and swift recovery.  If your dragon is suffering from hypocalcemia and having seizures, it may have broken bones or other related issues.

I'm not sure what to make of your question about the cost of a UVB light.  Hypocalcemia will kill a dragon if left untreated.  It causes softening of the bones, which become brittle and break easily, and deform.  It causes seizures and edema (swelling), and it causes death.