I will teach you how to make lace thongs for only a couple dollars.  It is mind blowingly simple and will take less than 10 minutes! You don't need to pay their expensive prices to get brand name lingerie. So, here are the step-by-step instructions:

Step 1.  Materials                                   

Stretch Lace Trim - 45" length, approx. 2" width (the length depends on size).
Cotton - about 3 square inches, try to match the color of your lace (if you wish).

Step 2. Cutting Lace

Waist band: cut two 14.5" pieces of lace
Crotch: cut two 8.5" pieces of lace

Step 3. Pinning Lace

Waist band.  Place the 14.5" pieces on top of each other, if the lace has a front side you want the fronts facing inwards.  Pin each end together, you should only use 2 pins total, one on each end.
Crotch: lay the 8.5" pieces out the same as the waist band (fronts facing inward).  Pin the pieces together by placing the pins down the center of the lace pieces.  When you are about 1.5" - 2" from the end curve the pins towards the corner of the lace.  See picture for assistance.

Step 4. Sewing Individual Pieces

Waist band: use serger to sew each end of the waist band together.  If you don't have a serger use a zig-zag stitch and make sure it hangs over the edge of the lace.
Crotch: use serger to sew along the line of the pins.  BE CAREFUL make sure you are doing this on the correct side.  What ever corner the pins curve to you want to sew on that side of the pins (see image).  If you don't have a serger first cut on the side of the pins you would have sewn on the serger, then use a zig-zag stitch and make sure it hangs over the edge of the lace.
The end of the crotch piece that gets wider will be on the front of the panties.

Step 5. Putting It All Together

Each end of the crotch piece will be sewn to the waste band where the waste bands meet.  So, as shown in the picture, the seam on the crotch line up exactly with the seam on the waist band.  Do this for both ends.  Noticed the seam is facing upwards for both the crotch piece and the waist band.
Sew them together with your sewing machine using the zig-zag stitch.  You will want to use a thread that is the same color as the lace b/c it will show up on the front of the underwear. 

Now try it out!