No real surprise that TPM chips have spiked in price. A lot of AM3 class machines and Intel Skylake etc that do not have a TPM chip integrated but have a header on the motherboard for a TPM.
Years ago a TPM was $30 but now they are $120 or more. Prices will soften once a new supply of TPM modules are manufactured to meet demand.
Asus, MSI et al all have TPM 2.0 devices that fit the motherboard.
Socket AM4 and recent Intel machines support TPM natively.