Certainly, finding affordable alternatives to high-end products like the One Size Primer can be a great way to save money while still maintaining a quality skincare routine. Here are some top recommendations:

1. NYX Professional Makeup Pore Filler Primer: This primer is a great alternative as it minimizes the appearance of pores and preps your skin for makeup application. It's enriched with Vitamin E to help nourish your skin.

2. Maybelline New York Baby Skin Instant Pore Eraser Primer: This lightweight primer leaves skin looking smooth and matte for prolonged makeup wear. It's non-comedogenic and suitable for all skin types.

3. e.l.f. Poreless Putty Primer: This primer has a unique putty-like texture that adheres to the skin to create a smooth canvas for makeup. It's infused with Squalane for hydration and has a velvety texture that blurs imperfections.

4. Revlon PhotoReady Perfecting Primer: This primer smooths and perfects skin, reducing the appearance of fine lines and pores. It's lightweight, easy to blend, and gives a flawless, airbrushed look.

5. Rimmel Stay Matte Primer: This primer is a great option for those with oily skin. It controls shine for up to 8 hours and minimizes the appearance of pores.

Remember, while these alternatives may not have the exact same formula as the One Size Primer, they offer similar benefits at a more affordable price point. Always patch test a new product to ensure it suits your skin type.