Hi Mooz!
I like the idea of a 40 gallon breeder tank. You can get an aquarium stand for it in time and decent filtration too.
Since you're on a limited budget acquire things as you can afford them. The tank first, the stand and then filtration. The filters are highly variable but I recommend the Cascade 1000 models that you can get online for about $99.00. Yes, a somewhat expensive filter but they are awesome and last for years.
Sorry about your thumbs and arthritis--many of us have this as we get into our 50s and 60s.
Once the filter is set up and running they aren't too difficult to service once every 6 weeks and you should be able to manage it.
I'll try and post up some pics tomorrow.
Another option is the sunsun cannisters going for 80 plus on amazon..priming is a lil annoyijg but once its up and running its a very inexpensive solution.