Yesterday I was playing with a new wide angle lens and discovered I could get really close to the subject. So today I had a play. The first photo is using a very expensive wide angle( Minolta MD 24mm VFC F2.8) The coin couldn't fill the sensor but you can see at a half stop between 5.6 & F8 it does produce a useable picture

That first wide angle is just too expensive to use as a macro.... but I also had a very cheap 28mm wide angle (minolta MD 28 f 2.8) the phot0 isn't so good ( I rushed it) and is blurred but it does demonstrate if you wanted to go cheap you could use a
cheap manual focus wide angle , nikon, canon and Minolta all produced, what are now cheap, wide angles (usually 28mm)

I believe there is a minolta 28mm F 3.5 that can be had for less than US$30.00
Note coin is a Half thaler aprox 20mm in diametre