I'm a little confused by this pair of sentences, what are "the bitcoins I spend"? "Fortunately, the $1800 I spend on the hardware has paid me back over 10x in

I'm a little confused by this pair of sentences, what are "the bitcoins I spend"? "Fortunately, the $1800 I spend on the hardware has paid me back over 10x in dollar amount. It will take me about another 6-9 months to break even on the bitcoins I spend due to the massive rise in value since I made the pre-order."