Cricut pens are wonderful, dont get me wrong and you can buy them from cricut.
But you can buy cheaper pens and markers, especially around back to school time at Walmart.
But the non cricut pens don’t fit in your cricut pen holder. I have bought the adapters you can find on ebay but two out of three of them don’t work, at least I couldn’t get them to work. I’m not an engineer.
Removing the pen holder
But I found something that does. If you buy the foam pencil grips at the dollar store you can make them fit. You get lots of them in a pack and all you have to do is take a craft knife and slit them down the side lengthwise so you can wrap the around the pens. Then remove the pen holder on your cricut. You can do this by pressing up from the bottom. I would try it the first time with the cricut turned off. It will make some grinding sounds. This is normal. The holder should just snap out.
Putting in the new pen
When it is out, place the pen you want to use, with the pencil grip wrapped around it, in the pen holder and close it. If there is a gap in the holder put that towards the back.
Adjust the height of the pen by putting a scrap piece of paper between your project and the pen and adjust the pen until it touches the scrap paper then pull it back up just a smidgen. The first few times you try this, you may have to adjust it slightly but it will work.
Putting the pen holder back
When you are done you will want to put the cricut pen holder back in. First remove the other pen with the pencil grip. Then grab the cricut pen holder with the small opening down. Next put it back in the holder on the cricut and push until it clicks. You may have to press fairly hard. Once it is in close the latch and insert the scoring tool just to make sure everything is in right. The scoring tool should sit just above the paper level.
You are done. Now you can use any pen you want in your cricut and it only cost a dollar for the pencil grip.