Your 50/1.8 is a decent portrait lens when used on a crop camera. A 50/1.4 is even better.... with some subtle image quality improvements, but mainly offering faster & more accurate/consistent AF, better build... might be able to find it used under $300.
85/1.8 is a "long portrait" lens on a crop camera like yours. Also good, but a different focal length that provides a tighter crop. Pretty hard to find even a used one for $300 or less.
Some folks like a little longer lens for portraiture, such as the Canon 100/2. You might find it used for a little over $300.
I use the 135/2 a lot on full frame camera for portraiture, but it might be a little long for most crop sensor cameras... You need plenty of working room to use it on an APS-C camera.
There are also "environmental portraits".... wider shots of people showing them in familiar surroundings, at work on something, etc. For that a 35/2, Sigma 30/1.4, or Canon 28/1.8 might be a good choice for use on a crop camera. A wider lens like this also is useful for couples, full length shots, small groupds. At times I've used 20/2.8, too. With a wider lens you have to be very careful about perspective distortion effects. If you get too close, it will make their nose look big in relation to their ears, for example. Wide lenses also cause anamorphic distortions at the edge of the image, such as making one arm look bigger than the other. Of the above, you might find the 35/2 used for under $300... but I don't think you'll find any of the others for less than $300.
Yes, some of the macro lenses can serve dual purpose... macro and portrait. But most do not have particularly large aperture (f2.8 instead of f1.8 or f1.4) and can even be too sharp for some types of portraiture. The relatively new Tamron 60/2 macro has an unusually large aperture for a macro lens and appears to have a lot of potential. I've had great luck with Tamron lenses over the years. But it's AF will likely be slower than the above non-macro lenses.
From your signature, it sounds as if you need to get your camera fixed or replaced before shopping for a lens!