After how long should one get tested for STD’s from the day he receives oral sex?

If someone receive unprotected oral sex (a guy receives it) after how long should he get tested for any STD’s? Also how long will it take to see any symptoms on his penis (genital)? How much it cost to get tested and does insurance companies cover it? What does the symptoms look like? I heard they were something like rash pimples and white spots?