If you never been to Thailand the request should be incorrect, but here is an info I give to those wanting to migrate to Au when they need a Thai PCC: Police Check - Thailand
Relevant document
‘Police Clearance Certificate’ provided by the Police Clearance Service Center (PCSC), Special Branch of the Royal Thai Police.
Citizens resident and non-citizens resident
Apply in person at the address below.
Documents required
clear copy of valid passport (must have at least 6 months validity)
photocopy of Thai ID card (for Thai citizens)
any evidence of name changes
household registration (for Thai citizens)
marriage certificate or divorce certificate (if available)
evidence of military service (such as Sor Dor 9, Sor Dor 8 or Sor Dor 48)
agreement from their employer (applying for work)
confirmation letter from university and student visa (applying for education)
written request for the certificate from the Department office processing your application, such as a Request for Record Check, or receipt of visa application, etc.
letter of consent (for applicants under 20 years old) to travel abroad issued from the District Office
for non-citizens, document(s) certifying they are/were working or living in Thailand, or a Thai work permit (if available).
Citizens not resident and non-citizens not resident
Application is by post or have a representative who applies on their behalf to the address below.
Complete and download the following forms from Police Clearance Service Centre (sbpolice.go.th):
Application for Police Clearance Certificate
Testimony Memorandum
Taking Fingerprint for Criminal Record Checking outside Thailand.
Documents required
photocopy of valid passport (must have at least 6 months validity)
photocopy of Thai ID card (for Thai citizens)
photocopy of household registration (for Thai citizens)
evidence of military service (for Thai male aged 17-45 years old)
photocopy of any change of name/surname certification
photocopy of Thai work permit/visa (for non-Thai citizens)
photocopy of current country of residence visa
photocopy of passport pages with all entry and exit stamps to/from Thailand (for non-Thai citizens)
2 passport size photographs
obtain 2 sets of hardcopy of original fingerprints at the Royal Thai Embassy of local police station in your country of residence
proof of payment (hard copy)
self-addressed envelope that covers return postage or pay an extra THB500 to UOB Bank for postage fees
if someone else is submitting the application on your behalf, power of attorney, revenue Thai Stamp THB10, and photocopy of representative's passport or Thai citizenship ID Card.
Fee
The standard processing fee is THB100 but may vary depending on the application to cover for postage fees.
If the applicant is residing abroad, they may:
get a representative to apply on their behalf and pay THB160 to the bank account below
send a prepaid self-addressed envelope and transfer THB100 to the bank account below
send a self-addressed envelope (not prepaid), and transfer THB600 to the bank account below.
Bank Name/Branch: UOB Bank/Siam Square Branch
Bank code: 024
Branch code: 772
Swift code: UOVBTHBK
Bank address: 410-
*****
Siam Square Soi 6, Rama 1 Road, Patumwan Sub District, Patumwan District, Bangkok, Thailand
A/C Name: Police Clearance Service Centre
A/C No.: 772-163-299-0
A/C Type: Savings
Note
All supporting documents must be certified true copy by applicant's signature.
The certificate fee and postage fee must be paid in Thai currency.
The applicant is responsible for all outgoing and incoming money transfer fees.
The application will not be processed until all required documents and payments have been made
I can comment on the 25k for the sc600 application as that is what i do for a living. It is reasonable (although i know it does not sound reasonable for many) and is quite an average number when it comes for sc600 applications for high risk countries. The goalpost has been moved by the department and the evidence required is more complex than a mortgage application. Your Au partner visa would set you back around $15-20k (that is AUD) depending on complexity. Love appears to be real expensive these days.
I cannot help you with the USA visa part. I am am an Australian Migration Agent and i can share some experiences as the US and Au are both pain to get into. In general, when i work with anyone from a perceived "high risk country" i prepare a very detailed submission with regards to incentives to return; address things that the Au government deems as genuine temporary entrant criterion (from local assets, family ties, long term employment and so forth). I am going to assume that this is similar to what the US want to see. You need to very much emphasize that you are going to visit, but you both reside permanently in Thailand and intend to do so in the long run. Best of luck