Two churches in Meteora. Meteora has 165 tickets and tours to book; Monastery of Rousanou has no online ticket listed. The table and the two notes below put them side by side; the full pages have what to see, the ticket and the timing for each.
Meteora is not one ticket but six. Each working monastery on the rock pillars charges its own small entrance fee at the gate, payable in cash, and each keeps its own closing day, so the practical question is how you get between them rather than what you buy. Driving yourself is cheapest and most flexible, since the road loops past every monastery with parking at each. Tours from the villages below, Kalabaka and Kastraki, run half-day and full-day versions that usually include three or four monasteries plus the transport, with the entrance fees often left for you to pay.
Rousanou is one of the six monasteries still active at Meteora, and it is the easiest to reach: a short path and a bridge lead from the road to the entrance, with far fewer steps than at the Great Meteoron or Holy Trinity. That makes it the best choice for visitors with limited mobility or little time. Entry is ticketed, cheaply. Rousanou is a convent run by nuns, and like the other monasteries it closes one day a week, usually Wednesday, so check before planning a route.