Disclaimer: I’m not a lawyer, so this isn’t legal advice.
Yes, you can include MIT licensed code in something you sell. The MIT license is very permissive. From the license:
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
Also, in contrast to copyleft licenses such as GPLv3, the MIT license does not require that you relicense the rest of your product.