None of the oils and oil-containing sauces and spreads that are available in just about every single supermarket store are trans-fat-free.
If you want to really buy good oils, except for butter and olive oil, you will need to buy your oils, mayonnaises and spreads from health food stores which carry un-refined oils. It is not good enough for the food producing company to have labeled their oil containing product as trans fat free. Read the ingredients label. Does the product include the words “ cold-pressed oil” or “ un-refined oil” and or "packed in nitrogen" ? Unfortunately even these labels do not necessarily indicate that the oil is safe from high temperatures. The term "cold pressed" or "expeller pressed" may simply mean that the oil has been extracted using a press and no external heat added. This terminology does does not rule out the possibility of high temperatures being generated by the action of the press itself. As well as this, refining processes which might follow the use of a "cold press extraction of the oil" will be just as damaging to these oils as these procedures are to any oil.
One rarely seen label you may see on an un-refined oil product would be " Modified Atmospheric Packing" (MAP). This method of oil extraction employs the use of an expeller press which is set up so that it will maintain a low temperature and maintain the pressing conditions free from impingement of light and oxygen. You will not likely see the term Modified Atmospheric Packing included in the labeling of an un-refined oil. However the trade names "Bio-Electron Process", "Spectra-Vac" and "Omegaflo" refer to this very technology as practiced by the companies Barlean's Organic Oils, Spectrum Naturals, and Omega Nutrition.
These Three companies produce high quality un-damaged oils which are genuinely cold pressed and handled with sufficient care to avoid damaging them.
You can buy health olive oil from a super market though. All olive oil is safe to use. Sometimes olive oil is mixed with cheap refined oils, so be sure that the olive oil that you are buying is pure. Virgin olive oil is the best, since it is pressed at the coolest temperatures, and with the least amount of pressure. However, cheaper olive oil which is extracted with the second pressing of the olives from which the virgin olive oil was pressed is still safe to use. It endured higher temperatures, and greater pressures than the virgin olive oil of the first pressing endured, but as far as you are concerned second pressing olive oil is still safe to use. You do not need to see the words “ cold-pressed” or “un-refined” on the label. Olive oil is a naturally stable oil. The highest temperatures that olive oil is exposed to during processing do not cause it damage, and once it has been pressed no refining is necessary for it to exhibit a very long shelf life.
All butter is safe too. You can buy it from any store. Butter is essentially an un-refined oil (or fat really) and is the best choice for high temperature cooking since it is mostly unsaturated. Unsaturated fats can endure a certain amount of above boiling temperature exposure without damage. Even so, be careful not to burn butter. Burned foods are chemically damaged (from a biological point of view) and butter is no exception.