bitcoin is divisable by 100,000,000 parts per coin. You do not need to buy one for 18,000.
Dont recommend buying any alt based on suggestions. Know what you own, dont buy without researching. If ya cant be botheres to do that, a reasonable lazy approach is to go with the top 5-10 alts by market cap. Generally true catastrophes of a bogus crypto dont make it into the top 10.