There are plastic compression fittings made for working with PEX, although they may not have the "install it behind a wall" trustworthiness of the conventional PEX crimp fittings. Also, since PEX is copper-tubing-sized material, one could use waterworks-quality compression fittings to connect to it. Either of those choices is far less expensive than the cost of owning your own crimpimg tools for conventional PEX fittings.
You shouldn't have to purchase a PEX crimper if you're only doing a fix here and there. A lot of hardware stores will rent the crimpers to you for a couple of dollars, and some will even lend them to you to use for a couple of hours if you purchase the fittings from them.
Mick