Don't listen to the haters, you can still get a great workout in without olympic gear. I used standard plates/bar for months before buying an olympic set.
With that being said, let me outline a few things for you.
Standard:
- Little to no resell value
- Lower quality weights which have a shorter life span
- Takes longer to add weights/collar (normally standard comes with a screw on that nearly takes a minute just to secure, HUGE pain adding/removing weight).
Olympic:
- Almost always a market for gear/high resell value
- Higher quality and much longer life span, the equip will outlast you if you treat it right (better knurling, thicker bar, can make for a much more enjoyable workout)
- Easily add/remove weights/collars
At the end of the day it's up to you, you can still get a great workout without the olympic gear, however I absolutely recommend you invest in olympic gear. If you do opt to go for standard gear, for the love of god, DO NOT buy new.
If you're tight on a budget check kijij/craigslist for used gear, especially if you're investing in standard gear. There's a reason you got the weights for free, you may manage to find a barbell/dumbbells for free as well..