It's not super practical to make objectives. While I suppose it's technically possible, what you produce will almost certainly be worse, more expensive, and more time-consuming.

$65 for a good lens is really not a huge amount of money; you can also find slightly cheaper lenses (about $20 on aliexpress).

To make a lens like this, you would have to buy a glass blank of the right type (two, actually- a doublet is made of two different types of glass), grind and polish them (very messy), and then bond them and apply an antireflective coating. Getting the lens geometry just right is very challenging. Or you can just give Thorlabs $65 and focus (ha) on building a microscope around it (I do this as a hobby; I'm sitting next to one of those lenses right now).

However, folks do this, see http://www.microscopy-uk.org.uk/mag/indexmag.html?http://www... but I can tell you from the images that you could get the same results (better really) with a $150 microscope (which also embeds many hundreds of years of practical technology that make your experience significantly better).

Also, if you're really keen on doing it yourself for pedagogical reasons, then have at it, I just don't think it's the best use of time.