DVD-R or DVD+R is.... 29.95 plus tax (8% = 2.40) plus 1.50 shipping and handling.  If you are not sure of +R or - R use this rule of thumb.  
1: Try finding it on the documentation.  
2:  If player is new, odds are it is +R
3:  If player is older an model, odds are it is -R

Note: Some old, old DVD players will not play either one.   However, your next player purchase will probably play either +R or -R.