Suppose it depends on the origin of the beta glucan.
Beta glucan can be drived from cereals (esp. oats) and from micro-organisms (esp. yeast). There are huge differences in the commercial scale and yield of these materials which, no doubt, corresponds to the price hike.
Are you claiming any special attributes to the ingredient (e.g “made from yeast”? If not, and you are just using it as a thickener, then the cheapest product that does what you want it to do will be better.
If you are making any natural claims, well, it is far from being natural - the beta glucan having undergone vigorous chemical modification.