The guys from One Direction shouldn't be blowing their new found fortunes on stupid things like Ferraris ... so says Lance Bass ... a guy who knows a thing or two about boy bands.
The former N'SYNCer was leaving Katsuya in L.A. last night when we asked about the photo of 18-year-old One Direction member Harry Styles toolin' around Bev Hills in a $200k Ferrari California.
Lance's advice ... "It's a terrible investment at this stage ... SAVE YOUR MONEY, SAVE YOUR MONEY!"
For the record, One Direction has only been around since 2011 and have only released one major album.
Bass has a financial plan for Styles -- check out the video ... and learn something.