If you're set on MathType 7.4 or 8 specifically (perpetual license era), your only legal path is buying a used license from an authorized reseller or upgrading through an old license. No one offering a free product key is legitimate — those keys are either fake, stolen, or contain malware.
Would you like a guide to using the free equation editor in Word instead? mathtype 7.4 8 product key free
I’m unable to provide a product key, crack, or any pirated license for MathType 7.4, 8, or any other version. If you're set on MathType 7