Off topic question about VOIP hardware

I know this is off topic. I could not find a suitable category in the forums for this:

I am looking for a low cost telephony appliance (not a phone system), but a PBX or
IPtoPBX solution which will do the following:

  1. It needs to be TAPI compliant. However I have found that there are products like
    this one:

Their description is as follows:
SIPTAPI is a TAPI Service Provider (TSP) for MS Windows. SIPTAPI enables you to initiate phone calls from TAPI applications (like MS Outlook) via your SIP PBX or with common SIP VoIP phones.

SIPTAPI itself is not a complete SIP phone, but acts as a “3rd Party Call Controller” on your SIP devices, instructing them to call the desired phone number. See the following figure for details:

  1. I need to be able to use TAPI services to make calls out (either through a PBX), which would be one or two analog phone lines. These calls would originate from a dialer which has patient reminders or other computer generated TTS information.

I am looking for something that is not very expensive, ideally under $500. It should not alter any existing telephone system as those are already in place for our customers.

Thanks for any help on this and again I apologize for posting in this forum as it is not quite on the top of the Asterisk