Hi Double C, of course cost is important and also what area of astrology you wish to study.
Most common program is Solar Fire, but I don't recommend it if you are into asteroids, in which case SIRIUS is better.
JANUS is good for Charles Carter type astrology with excellent Cosmogram triwheels.
Now, which program offers the best interpretations or add on programs. I don't use Solar Fire for this.
Halloran software is very economical and offer excellent interpretations of natal, lunar and solar returns, Black Moon Lilith interps,
parallel and contraparallel interps for males and females, etc., 45 and 135 degree interps in one's natal chart.
You can use PAINT to touch up charts and then move them to the Tyl site with any of the 4 programmes.
Not happy with Solar Fire's add on programs.