There is a lot of nuance to the subject not captured in my summary. Perhaps the monks were offering free blessed rosaries and you could make a free will donation for them?

From magisterium.com:

The Church teaches that a blessing is a **sacramental** – a sacred sign instituted by the Church that prepares the faithful to receive the grace of the sacraments[^1]. Because a sacramental is a “spiritual thing” belonging to the treasury of God, the Church forbids any **exchange of it for a temporal price**. The sin of such an exchange is called **simony**.

### 1. Simony and the sale of spiritual goods

The Catechism defines simony as “the buying or selling of spiritual things”[^2]. The Church’s magisterial documents repeatedly condemn the practice of putting sacred objects or blessings up for sale:

* The Fourth Lateran Council (1215) expressly forbids “the sale of relics” and, by extension, any commercial traffic in sacred objects[^3].

* The same council also condemns “the selling of blessings, the ordination of clerics, the consecration of bishops” as a grave abuse[^4].

* The *Catholic Encyclopedia* on Simony states that it is “unlawful … to sell blessed rosaries or crucifixes”[^5].

* The *Enchiridion Symbolorum* (Dz 364) adds that anyone who acquires any “ecclesiastical sacrament, namely chrism or holy oil, the consecrations of altars or of churches” by money is to be marked with disgrace[^6].

Thus, **selling a blessed rosary, a crucifix, a holy water font, or any other object that has received a Church blessing is a simoniacal act**.

### 2. Can a priest sell a blessing?

A priest may bless an object **free of charge**. The *Directory on Popular Piety and the Liturgy* stresses that a blessing “is an authentic expression of faith in God, the giver of all good things” and that it must be given “without the appearance of a price”[^7]. The Code of Canon Law (Can. 1167 § 2) requires that the rites and formulas for sacramentals be observed “carefully” and that they are established **by the Apostolic See alone**, not for commercial profit[^8]. Therefore a priest who receives money **specifically for the act of blessing** commits simony; a modest donation offered voluntarily after a legitimate blessing is permissible, but the blessing itself cannot be sold.

### 3. Does a blessed item lose its blessing when sold?

The blessing itself **remains** on the object; the sacramental effect is not automatically nullified by a change of ownership. However, the Church teaches that the **spiritual benefit attached to the object** (such as an indulgence) can be lost when the object is sold. The Baltimore Catechism notes that “things lose the Indulgences attached to them … when they are sold”[^9]. The loss of an indulgence does not mean the object is no longer a blessed sacramental, but it does indicate that the commercial transaction is illicit and deprives the faithful of the attached spiritual benefit.

### 4. Practical implications for the faithful

* **Monks or laypersons who sell blessed rosaries** are acting illicitly; the transaction is simony and the sale is prohibited.

* **A blessed object may be freely given, loaned, or bequeathed** without any loss of its sacramental character. The faithful should receive such items as gifts, not as purchases.

* **If you acquire a blessed object**, you do not need to have it re‑blessed simply because it changed hands; the original blessing remains valid. Nonetheless, you should avoid any situation that makes the blessing appear to have been bought for profit.

### 5. Summary

The Church’s teaching is clear:

1. Blessings are sacramentals, belonging to the spiritual treasury of the Church.

2. Simony—selling or buying spiritual goods—is gravely sinful; it includes the sale of blessed objects.

3. Priests may not charge for a blessing; any such charge is simoniacal.

4. A blessed item does **not** lose its blessing when sold, but the act of selling is illicit and may cause the loss of any indulgence attached to the object.

Faithful Catholics are therefore called to receive and distribute blessed sacramentals **as gifts of charity**, not as commodities for profit, preserving the dignity of the Church’s sacramental economy.

[^1] [Catholic Encyclopedia Blessing](https://www.magisterium.com/docs/f2c979a8-871d-4f46-a059-320d3b837a76/ref/Blessing)

[^2] [CCC 2121](https://www.magisterium.com/docs/0583c069-d4bf-42dd-97de-c19f0b80150f/ref/2121)

[^3] [Instruction "Relics In The Church: Authenticity And Preservation" Part I - Article 25](https://www.magisterium.com/docs/89316f28-bc5a-4165-9a64-3838ca7ca7bd/ref/Part%20I%20-%20Article%2025)

[^4] [Fourth Council of the Lateran (1215 A.D.) 63](https://www.magisterium.com/docs/0b302a3b-0545-4e89-822f-386deadd2499/ref/63)

[^5] [Catholic Encyclopedia Simony](https://www.magisterium.com/docs/f2c979a8-871d-4f46-a059-320d3b837a76/ref/Simony)

[^6] [The Sources of Catholic Dogma (Enchiridion Symbolorum) 715](https://www.magisterium.com/docs/17f50f07-de81-4bf5-997c-f41ee830c033/ref/715)

[^7] [Directory on Popular Piety and the Liturgy: Principles and Guidelines 272](https://www.magisterium.com/docs/4fba701f-fda0-47a5-a2de-2e210d81f770/ref/272)

[^8] [Code of Canon Law 1167](https://www.magisterium.com/docs/927224e3-8c2d-44ed-a9fb-dc736030081d/ref/1167)

[^9] [A Catechism of Christian Doctrine (The Baltimore Catechism No. 3) 866](https://www.magisterium.com/docs/8b7bf85b-c327-43eb-8c2c-85f0272f6ae6/ref/866)