There is no need to use a company to claim your entitlement to funds which have been escheated. If you contact the State holding the property, they will notify you of their requirements.
Usually, companies who seek to find those who have missing US property funds work under agreements whereby they keep a percentage of the asset which they assist you with. We frequently find that this percentage fee is out of proportion with the asset value and the work involved.
Conversely, if you are attending to an estate with escheated assets, and you are not based in the US, meeting the requirements of the relevant State can at times be a challenge. You may be required to provide affidavits of law as part of the claim. We always try to provide a fixed fee quote for such work and this is based more on the expected work involved rather than the asset itself.