$1 OPI nail polish DUPES?!?!?!?

I love OPI nail polish. Who doesn't right? What I don't like is the fact that I pay at least $40 every time I go to ulta to a few bottles or make an order online for OPI polishes. I've been buying OPI since I was in 10th grade. That's 7 years of paying $8.00 for bottles of nail polishes! YIKES! Recently I started experimenting and trying out cheaper brands just to see what I could find. I found a little gold mine known as....SINFUL COLORS! This week walgreens had their sinful colors nail polishes priced at just 99 cents so I thought "hey...good time to invest in some bottles and try it out!" $23 later and with the use of 2 great coupons....I have the entire collection of sinful colors available at my walgreens. Since I bought the sinful colors polishes I have not only realized that I have found a wonderful quality nail polish at a very decent price (even regularly they are still only $1.99), but I also discovered quite a few dupes for OPI polishes! What does this all mean? This means that I have found 99 cent nail polishes that are identical to $8.00 nail polishes! Here are pictures of some OPI polishes next to their identical sinful colors version:

SC: easy going 

OPI: sweetheart

SC: boom boom

OPI: don't know...beets me

SC: Bali mist

OPI: Significant other color

SC: Cloud 9

OPI: totally tangerine

(there is just a touch more shimmer in the OPI version in the bottle, but the color and finish comes off extremely close to identical once applied to your nails.)

SC: thimbleberry

OPI: mod-ern girl

(this sinful colors polish is also very similar to nicole alert or cajun shrimp from OPI. It is only slightly off)