Having had quite luxuriant hair in my youth, it came as a bit of a shock when my hair started thinning. After much trying and eliminating, I currently use any ordinary shampoo, followed by a small amount of John Frieda Luxurious Volume. After towel drying, I use a golf ball sized blob of John Frieda Volume Building Mousse. These products have made a visible difference that my friends have noticed. As you only need to use small amounts, they last for ages. Sold at most supermarkets.
Good luck with your trials!
The King is to resume some duties.